Question

My teacher gave me a sheet of this and no instructions:

1. 5x+2y=10
-5x+7y=8

I don't know what I am suppose to do.

Answer 1

probably wants you to find what numbers will work for x and y in both equations

add the two equations together
5x-5x+2y+7y=10+8
9y=18
divide both sdies by 9
y=2
subsitute into first equation
5x+2(2)=10
5x+4=10
subtract 4 from both sides
5x=6
divide both sdies by 5
x=6/5


so the asnwer is x=6/5 and y=2