A system of equations is shown below. y = 5x + 10 y = 10x – 5 What is the value of x + y? A. 25 B. 28 C. 72 D. 75

Question

asked Jul 1, 2020 154k views

1 Answer

Wendy Liga · Answer 1 · 2020-07-06T02:59:50+0000

Answer:

B. 28

Explanation:

We are given the following system of equations

$y=5x+10\\y=10x-5$

We can substitute in one of the equations for y. This will give us an equation that we can solve for x.

$5x+10=10x-5\\\\5x=15\\\\x=3$

Next we can substitute in our value for x in order to find the y value.

$y=5(3)+20\\\\y=15+20\\\\y=25$

Now we can check with the other equation to see if our x and y values are correct

$25=10(3)-5\\\\25=30-5\\\\25=25$

Now we are certain that x=3 and y=25

$x+y=?\\\\3+25=28$