Answers
Looking at the first system of equations,
16x - 10y = 10
-8x - 6y = 6
If we multiply both sides of the second equation by 2, the coefficient of x is exactly the negative of the coefficient of x in the first equation.
-8x - 6y = 6
⇒ 2 (-8x - 6y) = 2 (6)
⇒ -16x - 12y = 12
By combining this new equation with the first one, we can eliminate x and solve for y :
(16x - 10y) + (-16x - 12y) = 10 + 12
⇒ -22y = 22
⇒ y = -1
Then we just solve for x by replacing y in either equation.
16x - 10y = 10
⇒ 16x - 10 (-1) = 10
⇒ 16x + 10 = 10
⇒ 16x = 0
⇒ x = 0
The main idea behind elimination is combining the given equations in just the right amount so that one of the variables disappears. The "right amount" involves using the LCM of the coefficients of a given variable. In this example, the x-coefficients had LCM(8, 16) = 16, so we only had to scale one of the equations (the one with -8x) to cancel all the x terms.
If we wanted to eliminate y first instead, we first note that LCM(6, 10) = 30. To get 30 as a coefficient on y, in the first equation we would have multiplied by 3:
16x - 10y = 10
⇒ 3 (16x - 10y) = 3 (10)
⇒ 48x - 30y = 30
And in the second equation, we would have multiplied by -5 (negative so that upon combining the equations, we end up with -30y + 30y = 0):
-8x - 6y = 6
⇒ -5 (-8x - 6y) = -5 (6)
⇒ 40x + 30y = -30
Now combining the two scaled equations gives
(48x - 30y) + (40x + 30y) = 30 + (-30)
⇒ 88x = 0
⇒ x = 0
We then solve for y :
16x - 10y = 10
⇒ -10y = 10
⇒ y = -1
so we end up with the same solution as before.
Related Questions
Where did this student make the mistake when solving this inequality?
2x + 4 > 5x - 5
-2x -2x
4 < 3x - 5
+5 +5
9 < 3x
/3 /3 (divide by 3)
3 < x
options:
When subtracting the same value from both sides you don't need to switch the inequality sign
There is no mistake, it was solved correctly
You don't subtract 2x from each side, you add 2x to each side
When dividing by 3 you should switch the inequality sign
Answers
Answer:
You don't subtract 2x from each side, you add 2x to each side
A swimming pool already contains
a small amount of water when you start filling it at a
constant rate. The pool contains 45 gallons of water after
5 minutes and 120 gallons after 30 minutes. Find the
average rate of change and use it to write a linear model
that relates the amount of water in the pool to the time.
Answers
Answer:
Rate of change = 3 gallons/minute
Starting volume = 30 gallons
Step-by-step explanation:
A graph of the pool's water level would be useful. The slope of the line would represent the rate of change for filling the pool. It will also help us determine the amount of water that was in the pool to start. Although it is tempting to say the rate of fill is 45gallons/5 minutes, or 9 gallons/minute, it is not correct. The pool already started with an unknown volume of water. The rate of change after 5 minutes, however, can be used. The problem states it is being added at a constant rate. Let's find an equation for a line, in the format of y=mx+b, where m is the slope (rate of change) and b is the y-intercept.
We'll let y represent the volume of water in the pool, and x will be the time in minutes. The y-intercept will give us the amount of water in the pool at the start (x = 0).
The slope can be determined between the two given points:
(5,45) and (30,120):
Slope = Rise/Run [The change in y divided by the change in x].
Rise = (120 - 45) = 75
Run = (30-5) = 25
Slope = 75/25 or 3
The line, so far, becomes y=3x + b
The slope of 3 has units of gallons/minute. It is the rate at which the pool is being filled.
We can find b, the starting volume of water, by using one of the two points in the equation and solving for b:
y=3x + b [I'll use (5,45)]
45 = 3*(5) + b
b = 30 gallons
The pool had 30 gallons to start (at x = 0(minutes))
See the graph of the line, attached.
What is an expression equivalent to 25x^2+28x+16
Answers
The FitnessGram™ Pacer Test is a multistage aerobic capacity test that progressively gets more difficult as it - IM JUST KIDDING I ACTUALLY NEED HELP THO
Answers
Therefore, we can create an equation to find the measure of angle 1, given the two other angles.
76+59+x=180. x=the measure of angle 1 (unknown).
135+x=180. [76+59=135]
135-135+x=180-135 [Isolate x by subtracting 135 from both sides]
x=45.
Therefore, the angle measure of angle 1 = 45°
a student answered 86% of the questions on a test correctly. he received a grade of 98%. how many questions were on the test?
Answers
Let the number of questions on the test equal X which would be 100%
They answered 86 which equaled 98
Set up a ratio:
X/86 = 100/98
Cross multiply:
98X = 8600
Divide both sides by 98:
X = 87.75
Round to 87 questions
HELLO EVERYONE
WHAT IS THIS ANSWER??? ANYONE KNOW? i need help on this question. it is kinda confusing but if anyone knows pls txt back to this post. thank you so much and have a good day.
Answers
Answer: The volume of this cylinder is 2389.18 cubic cm, and the surface area is 1000.6 square cm.
convert NPR 180000 into
1. USD
Answers
Answer:
Solution here,
1 US dollar=NRS 120.74
Therefore Rs 180000= 180000/120.74
=$1490.99
−
3
x
+
y
=
−3x+y=
−
3
−3
−
6
x
+
2
y
=
−6x+2y=
−
3
−3
Answers
Answer: -3x+4
Step-by-step explanation:
combine like terms.
3x+ -6x=-3
-3+-3+2= -4
-3x + -4
Solve the system of equations
X=11+y
2x+y=19
Answers
Answer:
Step-by-step explanation:
To solve this system of equations, let's first find the value y. We can replace the x in the second equation with 11 + y, since we are told in the first equation that x is equal to 11 + y. So, let's replace x:
2(11 + y) + y = 19
22 + 2y + y = 19
22 + 3y = 19
3y = -3
y = -1
And look at that - we've found our y-value! Now, we can replace the y in the first equation with -1 to find the value of x.
x = 11 + (-1)
x = 10
So, the solution to this system of equations is (10, -1). Hopefully that's helpful!
2 1/3 divided by 1 1/5 what is the answer as a fraction or mixed number in simplest form?
Answers
Answer:
1.9444444 is the answer or 35/18
Step-by-step explanation:
Answer:
10/3 or 3 (1/3)
Step-by-step explanation:
I used a calculator sorry i don't know how to explain it
PLEASE HELP!! 100 points!!!
The angle of depression from the top of a tower to a boulder on the ground is 22 . If
the tower is 70 feet high, how far from the base of the tower is the boulder? (Round
answer to the 1st decimal place.)
Answers
Answer:
173.3 feetStep-by-step explanation:
Let the required distance be x.
We have a right triangle with vertical leg of 70 feet and the acute angle opposite to this leg is 22 degrees.
Use trigonometry:
adjacent / opposite = cotangentx / 70 = cot 22 degx = 70 cot 22 degx = 173.3 feet (rounded)Please HELPPP!! Thank you
Answers
Answer:
its 6,7 just make it right if im wrong
i need to find the zeros by factoring but im stuck plss help me i think the zeros may be 0, 1, -4, and 4 but i dont know how to get them??
Answers
In this case. Factor by grouping, then you will have several parenthesis multiplied by each other. Set each to zero
Need some help if u don’t mind :)
A)94
C)82
C)76
Answers
Answer:
82
Step By Step Explanation:
I would have choose 86 but there is no 86 since 82 is closer I choose it.
A full angle equals 180 so 180-94=86.
Hopes This Helps
Calculate the area of the triangular region determined by the points D(-4,3) E(-7,-8) F(-2, -3)
Answers
Answer:
The area is 27
Step-by-step explanation:
Area =1/2 [x1(y2 - y3) + x2(y3 - y1) + x3(y1 - y2)]
Area =1/2 [2(-6 - 8) + 3(8 - 4) + 7(4 + 6)]
=1/2 [2(-14) + 3(4) + 7(10)]
=1/2 (-28 + 12 + 70)
=1/2 (54)
Area = 27
Solve the equation. Please
Answers
Answer:
y=3
Step-by-step explanation:
1/4 = 3/12
Based on the information in the table, how much will Henry earn if he worked 7 hours?
A
$48
+
B
$72
С
$9
D
$63
Answers
Answer:
D.
Step-by-step explanation:
One research study of illegal drug use among 12- to 17-year-olds reported a decrease in use (from 11.4% in 1997) to 9.8% now. Suppose a survey in a large high school reveals that, in a random sample of 1046 students, report using illegal drugs. Use a 0.05 significance level to test the principal's claim that illegal drug use in her school is below the current national average.
Answers
Using the z-distribution, it is found that since the test statistic is more than the critical value for the left-tailed test, it is found that there is not enough evidence to conclude that illegal drug use in her school is below the current national average.
At the null hypothesis, it is tested if drug use in her school is not below the national average, that is:
[tex]H_0: p \geq 0.098[/tex]
At the alternative hypothesis, it is tested if it is below, that is:
[tex]H_1: p < 0.098[/tex]
The test statistic is given by:
[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]
In which:
[tex]\overline{p}[/tex] is the sample proportion. p is the proportion tested at the null hypothesis. n is the sample size.93 out of 1046 reported using illegal drugs, hence the parameters are:
[tex]n = 1046, \overline{p} = \frac{93}{1046} = 0.0889, p = 0.098[/tex]
Hence, the value of the test statistic is:
[tex]z = \frac{\overline{p} - p}{\sqrt{\frac{p(1-p)}{n}}}[/tex]
[tex]z = \frac{0.0889 - 0.098}{\sqrt{\frac{0.098(0.902)}{1046}}}[/tex]
[tex]z = -0.99[/tex]
The critical value for a left-tailed test, as we are testing if the proportion is less than a value, is [tex]z^{\ast} = -1.645[/tex]
Since the test statistic is more than the critical value for the left-tailed test, it is found that there is not enough evidence to conclude that illegal drug use in her school is below the current national average.
To learn more about the use of the z-distribution to test an hypothesis, you can take a look at https://brainly.com/question/25584945
solve the equation 5x+x-7=4x-2-x
Answers
Answer:
[tex]x=\frac{5}{3}[/tex]
Step-by-step explanation:
Brainliest pls?
PLEASE HELP ME 50 POINTSS 1!1!1!1!1!1!1!1!1!11!1!1!1!
How long does it take a baseball moving with an average
speed of 35 m/s to travel 18 m?
What is the average speed of a car that travels 870 km in 14.5
h?
Answers
Answer:
1) the baseball will take approx 0.514 seconds to move 18 meters.
35/1 = 18/x
x = 0.514s
2) the car's average speed is 60 km per hour.
870/14.5 = x/1
x = 60h
You have 64 inches of blue
fabric and 96 inches of green
fabric. You want to cut the fabric
into pieces of equal length with
no leftovers. What is the greatest
length of the pieces that you can
make?
Answers
Answer:
Step-by-step explanation:
48 times for the green fabric
32 for blue
what is the greatest common factor of 32 and 56
Answers
Five swimmers are entered into the competition. Four of the swimmers have had their turns. Their scores are 9.8s, 9.75s, 9.79s, and 9.81s. What score must the last swimmer get in order to win the competition?
Answers
Answer:
We must order these decimals from least to greatest. Then we must determine how the least compares with the winning score.
9.80 -> 3
9.75 -> 1
9.79 -> 2
9.81 -> 4
The least decimal is 9.75. Now we must determine how 9.75 compare with the winning score.
The last swimmer must get a score less than 9.75 s in order to win.
Step-by-step explanation:
Hopes this helps
Answer:
less than or equal to 9.74.
Someone please help
Answers
If AB∥ED and m∠ABC = m∠DEF. Prove CB|| EF.
Answers
Explanation:
( ) . . . . stuff that is given
∠ABE ≅∠DEG . . . . corresponding angles at a transversal
∠ABC +∠CBE = ∠ABE . . . . angle addition postulate
∠CBE = ∠ABE -∠ABC . . . . subtraction property of equality
∠DEF +∠FEG = ∠DEG . . . . angle addition postulate
∠FEG = ∠DEG -∠DEF . . . . subtraction property of equality
∠FEG = ∠ABE -∠ABC . . . . substitution property of equality
∠CBE = ∠FEG . . . . substitution property of equality
CB║EF . . . . converse of corresponding angles theorem
Derek and Jeannine buy a car for a total price, including tax, of $19,795. The price of the car was $18,500. What is the tax rate.
Answers
Answer:1.07
Step-by-step explanation:
Select the statement that is true.
0.969 < 0.967
0.967 > 0.969
0.967 = 0.969
0.967 < 0.969
Answers
Answer:
d option
Step-by-step explanation:
(d) option is true, as 0.969 is greater than 0.967.
Rest all options are false.
Hope it helps :)
please Help NEED NOW
thank you so much
Answers
Which statement is true about the equation 4.5z = 4.5z − 4.25 + 6.25? It has no solution. It has one solution. It has two solutions. It has infinitely many solutions.
Answers
Answer:
it has infinitely many solutions
Step-by-step explanation:
hope it help bro
Answer:
d
Step-by-step explanation:
Given this graph of the function f(x) a) b) c) d) please a need help
Answers
Answer:
a) 2
b) -2
c) -2
d) 1/2
Step-by-step explanation:
1) f(-4) means that x=-4 and you must locate the y value on the graph
2) f(2) means that x=2 and you must locate the y value on the graph
3) f(x)=4 means that y=4 and you must locate the x value on the graph
4) f(x)=-1 means that y=-1 and you must locate the x value on the graph