tìm m để phương trình có 1 nghiệm duy nhất
x+2y-2z=2
3x+7y-z=5
2x+4y+mz=7
Rewrite the system of equations in matrix form.
[tex]\begin{bmatrix}1&2&-2\\3&7&-1\\2&4&m\end{bmatrix} \mathbf x = \mathbf b[/tex]
This system has a unique solution [tex]\mathbf x = \mathbf A^{-1}\mathbf b[/tex] so long as the inverse of the coefficient matrix [tex]\mathbf A[/tex] exists. This is the case if the determinant is not zero.
We have
[tex]\det(\mathbf A) = m+4[/tex]
so the inverse, and hence a unique solution to the system of equations, exists as long as m ≠ -4.
Hamad go to buy toys for his smaller brother and he have only 5 AED each toy 1 AED cost. how much toys he will buy?
Answer:
5 because its 1 aed so if he buys 5 toys it will be 5 aeds and bye!
Step-by-step explanation:
because its 1 aed so if he buys 5 toys it will be 5 aeds and bye!
A department store sells a pair of shoes with a 15% discount. The original price of the shoes is $75. What is the sale price?
Answer:
$63.75
Step-by-step explanation:
10% = 7.5
5% = 3.75
15% = 11.25
75.00
-11.25
63.75
Help help help help help help help help help
Answer:
-4
Step-by-step explanation:
if you add negative 4 to each of the x's, it would give you the number of y
Answer:
-4
Step-by-step explanation:
the explanation is up in my answer
In physics, the equation PV = nRT is called the ideal gas law. It is used to approximate the behavior of many gases under different conditions.
P, V, and T represent pressure, volume, and temperature, n represents the number of moles of gas, and R is a constant for the ideal gas. Which equation is solved for T?
A: PV/R = nT
B: PV/nR = T
C: T= PV - nR
D: PVnR = T
Answer:
Option B
Step-by-step explanation:
[tex]PV = nRT\\\rule{150}{0.5}\\\rightarrow \frac{PV = nRT}{nR}\\\\\rightarrow \boxed{\frac{PV}{nR} = T}[/tex]
Hope this helps.
The equation for T will be;
⇒ T = PV/nR
Where, P, V, and T represent pressure, volume, and temperature, n represents the number of moles of gas, and R is a constant for the ideal gas.
Option B is true.
What is Linear equation?
When in an equation the highest power of variable is one then its called Linear equation.
Given that;
The equation for the ideal gas law is,
PV = nRT
Where, P, V, and T represent pressure, volume, and temperature,
n represents the number of moles of gas, and R is a constant for the ideal gas.
Now,
Solve the equation for T as;
PV = nRT
Divide both side by 'nR' we fet;
PV/nR = nRT/nR
PV/nR = T
T = PV/nR
Thus, The equation for T will be;
⇒ T = PV/nR
Learn more about the linear equation visit:
https://brainly.com/question/85774
#SPJ5
How would I simplify these expressions? (Pre-Calculus) I know that you are supposed to multiply all of these to do so, but every time I do that, I still get the wrong answer. My textbook says that these are the answers:
19: -15 + 8i
21: 8 + 6i
23: 34
25: 85
Could anyone explain how they got these answers? Mine are way off. Is the book just wrong? In #21, how would 3 times 3 equal 8 in the answer? Am I missing something?
Since you have the answers, I'll just show the steps on how to get there.
============================================================
Problem 19
[tex](1+4i)^2\\\\(1+4i)(1+4i)\\\\1*1 + 1*4i + 4i*1 + 4i*4i\\\\1 + 4i + 4i + 16i^2\\\\1 + 4i + 4i + 16(-1)\\\\1 + 4i + 4i-16\\\\(1-16) + (4i+4i)\\\\(1-16) + (4+4)i\\\\-15 + 8i\\\\[/tex]
Keep in mind that [tex]i = \sqrt{-1}[/tex] by definition. Squaring both sides leads to [tex]i^2 = -1[/tex]
In the second step, I used the idea that x^2 = x*x. Right after that, I used the FOIL rule to expand everything out.
============================================================
Problem 21
We could follow the same idea as problem 19, but I'll use a different approach.
[tex](A+B)^2 = A^2+2AB+B^2\\\\(3+i)^2 = 3^2 + 2*3*i + i^2\\\\(3+i)^2 = 9 + 6i - 1\\\\(3+i)^2 = 8 + 6i\\\\[/tex]
The formula on the first line is the perfect square binomial formula.
============================================================
Problem 23
The FOIL rule can be used if you want, but I'll use the difference of squares rule instead.
[tex](m+n)(m-n) = m^2 - n^2\\\\(3+5i)(3-5i) = (3)^2 - (5i)^2\\\\(3+5i)(3-5i) = 9 - 25i^2\\\\(3+5i)(3-5i) = 9 - 25(-1)\\\\(3+5i)(3-5i) = 9 + 25\\\\(3+5i)(3-5i) = 34\\\\[/tex]
It turns out that multiplying any complex number of the form a+bi with its conjugate a-bi will result in a purely real number (that has no imaginary part). More specifically: [tex](a+bi)(a-bi) = a^2+b^2[/tex]
============================================================
Problem 25
We could use the difference of squares rule again, but I'll show a different approach. This time using the distribution rule. The FOIL rule could also be used if you wanted.
[tex](6+7i)(6-7i)\\\\x(6-7i)\\\\6x-7xi\\\\6(x)-7i(x)\\\\6(6+7i)-7i(6+7i)\\\\6(6)+6(7i)-7i(6)-7i(7i)\\\\36+42i-42i-49i^2\\\\36-49(-1)\\\\36+49\\\\85\\\\[/tex]
I used x = 6+7i and the substitution property to help distribute. Lines 3 and 6 are where distribution is applied.
What is the quotient of 15a4b3/12a2b ? Assume that the denominator does not equal zero.
Answer:
[tex]\frac{5a^2b^2}{4}[/tex]
Step-by-step explanation:
write an equation with the two given points (7, -2) (-1, 0)
Answer:
haha.A. Write True if the statement is correct and False if it is not true. 1. In active voice, the subject of the sentence is doing the action, 2. In passive voice, the action is done on/upon the subject. 3. The doer of the action is followed by the verb in active voice. 4. The doer of the action is preceded by the verb in active voice, 5. The receiver of the action in active voice is preceded by the verb. 6. The receiver of the action in passive voice is followed by the verb. 7. In passive voice, meaning is clearer and more direct. 8. In active voice, meaning can be confusing and indirect, 9. The tone is authoritative and subjective in active voice, 10. The tone is neutral or objective in passive voice.
Find the sum of the pair of numbers.
8+(-2)
Answer:
6
Step-by-step explanation:
8-2
=8+-2
=6
the sum just means when u add them both together hope this helps! u just do 8 take away 2 because its a negative
dont sound so smart doing it she will know
Jeremy is incorrect because a negative plus a negative will always be a negative.
Write each number as a logarithm with base 3.
The answers has to be in this form: log .....
3
A) 0
B) -2
C) 4
Please answer. Correct answer gets BRAINLIEST ! Please don't ignore this.
An employee worked 36 hours last week. This week, she worked 48 hours. Find the percent increase. Round to the nearest percent. O 25% increase 0 33% increase O 12% increase O 75% increase
Answer:
See below:
Step-by-step explanation:
Hello! My name is Galaxy and I will be helping you today!
We can solve this problem in two steps, one is Comprehending and another is Solving. I'll start off with Comprehending.
Comprehending
We can start off by looking at the problem, it wants us to find the percentage increase from 36 to 48. We can then find difference between 48 and 36; that would be 12.
Now that we know the increase from 36 to 48 is 12. We need to find how much percent 12 is of 36.
Now that we know what we have to do, we can start solving.
Solving
We can solve the problem by setting up and equation, but we can also just use our logic in finding it out.
Since we know that we need to find how much 12 is of 36, we can just solve for that and we will get our answer.
We can do that with one step.
[tex]\frac{12}{36}=0.33[/tex]
Since it is a percent, we can multiply 0.33 by 100 and we get our answer of 33%
An elliptically shaped garden is surrounded by a wood walkway. The garden is 15 meters long and 8 meters wide. The walkway is 2.5 meters wide. Find the standard equation describing the ellipse formed by the walkway.
Answer:
x^2/b^2 + y^2/a^a = 1
Step-by-step explanation:
I believe that is the answer, also theanswerme answered this question. :)
geometry math problems
which one would be the correct answer
=======================================================
Explanation:
Your teacher wants you to use the angle-angle-side congruence theorem, which abbreviates to AAS. Note in the diagram that we have two pairs of angles marked.
Angle P = Angle U (double arcs)Angle Q = Angle S (single arcs)So we have the info about the angles being congruent, and that takes care of the two "A"s in AAS.
We just need a pair of sides to be congruent. Specifically, we need the pair of sides that are not between the angles mentioned for either triangle. If we went for this option, then we'd go for ASA instead of AAS. The order is important.
So we have two possible answers
PR = UTQR = STIf either of those were given to us, then we can use the AAS theorem. Unfortunately PR = UT isn't listed, but QR = ST is listed. So this is why choice B is the answer.
Side note: Both QR and ST are opposite the double arc angle.
Answer:
QR≅ST
Step-by-step explanation:
With AAS congruence, you need 2 angles and a non-included side. On ΔPQR, that could be either PR or QR. PQ is the included side as it is between the angles, and therefore cant be used for this congruence theorem.
As said above, it can be either PR or QR, but it has to be QR in this case as there is no answer option for PR.
On the other triangle, the corresponding side is ST. ∠S and ∠Q are corresponding, and US is the included side, so that leaves only ST.
Finally, the information you need to prove that the triangles are congruent is QR≅ST.
How do I do this math !
Answer:
The equation of a straight line is always
[tex]y=mx+b[/tex]
The constant m always refers to the slope, and the constant b always refers to the y-intercept.
Simply substitute the numbers in:
[tex]y=-\frac{1}{2}x+3[/tex]
There's your equation!
156) If x= 2in X A) P= 6.28 in B) P= 10.5 in C) P= 12.57 in D) P= 18.34 in
Answer:
P = 6.28
Step-by-step explanation:
To find the perimeter of a circle, you would use the formula 2πr.
The diameter = x and x = 2
The radius of a circle is half the diameter so r = 1.
Now we just substitute to get our answer:
2 · [tex]\pi[/tex] · r = P
2 · 3.14 · 1 = P
6.28 · 1 = P
6.28 = P
P = 6.28
If oranges are sold at ₹45 per dozen, Manu can buy 6 dozens of them with the money he has. Find the decrease in the number of oranges that he can buy if the cost is increased by ₹9 per dozen
Answer:
first 45-6=36 and 36×6=216 the answer is 216
PLEASE HELP WITH THIS ONE QUESTION
Answer:
Third one down
Step-by-step explanation:
Write the equation of the line that passes through the points (-9,9) and (8, -2).
Put your answer in fully reduced point-slope form, unless it is a vertical or horizontal
line.
Answer:
y + 2 = (11/17)(x - 8)
Step-by-step explanation:
Working with the x- and y-components of the given points, we see that the x component increases by 17 and the y-component decreases by 11. Thus, the slope of this line is m = rise / run, or 11/17.
Start with the general point-slope form: y - k = m(x - h) and use the coordinates of the 2nd point for h and k in this equation:
y + 2 = (11/17)(x - 8)
This is based on the point (-2, 8)
and the slope 11/17.
This result is the desired equation in point-slope form. If we wish to reduce this, proceed as follows:
17(y + 2) = 11x - 88, or 17y + 34 = 11x - 88
This last result simplifies to 17y = 11x - 54, or y = (11/17)x -54/17 (which is in slope-intercept form).
Given the triangle below, find the value of x
Answer:
I think it is b I’m not quite sure though. Sorry if wrong…
Step-by-step explanation:
ou have space in your garden for 60 small flowering bulbs. Crocus bulbs cost $0.45 each and daffodil bulbs cost $0.65 each. Your budget allows you to spend $35.00 on bulbs. How many crocus bulbs and how many daffodil bulbs can you buy
9514 1404 393
Answer:
20 crocus40 daffodilStep-by-step explanation:
Let d represent the number of daffodil bulbs you buy. Then 60-d is the number of crocus bulbs. The total cost will be ...
0.45(60 -d) +0.65(d) = 35.00
27 +0.20d = 35
0.20d = 8 . . . . . . . . . subtract 27
d = 40 . . . . . . . . . . multiply by 5
60 -40 = 20 . . . . . crocus bulbs
You can buy 20 crocus bulbs and 40 daffodil bulbs for $35.
On Monday, Elsbeth’s bank account balance was -$16.75. On Tuesday, she deposited a check for $5.72. On Thursday, she deposited $16.75. What is her new balance?
-16.75 + (5.72 + 16.75)
Use the commutative property to get:
-16.75 + (16.75 + 5.72)
Use the associative property to get:
(-16.75 + 16.75) + 5.72
Answer:
5.72
Step-by-step explanation:
(-16.75 + 16.75) = 0
0 + 5.72= 5.72
Therefore, the answer is 5.72
Kim, Jenny, and Wendy are basketball players. Each plays a different position (guard, forward, and center) and wears a different number (30, 32, and 35). Kim and number 30 are too small to play center. Number 35 in the center. Neither Kim nor Wendy is the forward. Who plays guard, and what uniform number does she wear? Be sure to check both answers. A.30 B.Wendy C.Jenny D.Kim E.35 F.32
Answer:its f
Step-by-step explanation:
the only answer left i hope this helps =)
Can some help me please I did one but I am not sure if it is correct.
thank you
Answer:
yes its correct
Step-by-step explanation:
but for the check where did you get the 12? you might want to redo that part but otherwise its right
PLZ HURRY IT'S URGENT!!!!
Find the area of the circle to the nearest hundredth. (Use 3.14 for π)
options:
452.16 cm2
37.68 cm2
113.04 cm2
18.84 cm2
Answer:
113.04 cm^2
Step-by-step explanation:
To find the area, you do radius squared, multiplied by [tex]\pi[/tex]
Radius is half of the diameter. 12/2 is 6
6^2×3.14=113.1
I'm DJ music is my hobbies what about you:)
Answer:
Playing video games or sumthin
Kevin Went for a drive in his new car. He drove at a speed of 56 miles per hour for 358.4 miles. for how many hours did he drive?
Answer:
Kevin Drove For 6 Hours and 40 Minutes
Step-by-step explanation:
56 times 6.4 Equals 358.4
Convert it into miles 56MI X 6.4(HR) = 358.4MI
let's substract : (2x + 3y) from (8x + 6y)
[tex]\huge\mathfrak\pink{answer} [/tex]
Brian has half of his investments in stock paying a 5% dividend and the other half in a stock paying 9% interest. If his total annual interest is $420, how much does he have invested?
The amount invested in each stock, the stock interest rate and the
duration of the investment, determines the interest.
Brian invested $3,000 in the stock that pays 5% dividend and $3,000 in the stock that pays 9% to make a total investment of $6,000.Reasons:
Let X represent the sum of the amount Brian invested, we have;
Amount invested in stock paying 5% dividend = [tex]\dfrac{X}{2}[/tex]
Amount invested in stock paying 9% dividend = [tex]\dfrac{X}{2}[/tex]
Total annual interest = $420
Required:
The amount invested in the stocks
Solution:
The amount invested is found as follows;
[tex]\dfrac{X}{2} \times 5\% + \dfrac{X}{2} \times 9\% = 420[/tex]
0.025·X + 0.045·X = 420
0.07·X = 420
[tex]\displaystyle \mathrm{The \ amount \ invested , \, X} = \frac{420}{0.07} = \mathbf{ 6,000}[/tex]
The amount he invested = $6,000 ($3,000 in each stock)
Learn more here:
https://brainly.com/question/20612739
On the following set of axes, create the graph of a function f (x) with the following characteristics:
Passes through the points,
(-8,0), (5,-2) and (8,3)
Functions can be represented on graphs and graphs can also be represented as functions.
The given parameters are:
Points = (-8,0), (5,-2) and (8,3)
Absolute Maximum = (-4,5)
Absolute Minimum = (2,-6)
Start by plotting the points (including the absolute maximum and the absolute minimum) without connecting the dots (see attachment 1)
The decreasing interval [tex]\mathbf{-4 \le x \le 2}[/tex] implies that the graph decreases from x =-4, to x =-2
See attachment (2) for the rough sketch of the graph that represents the given points and the decreasing interval
Read more about graphs at:
https://brainly.com/question/19277419