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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

User PeiSong
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1 Answer

3 votes

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

User Wendy Liga
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