5x+2y+-25 x-2y+7

Question

5x+2y+-25 
x-2y=7

 

Answer 1

I am guessing you have to find where these lines intercept? and the first one is equal to zero?

To do this we just sub one into the other. So taking the bottom one: 2y=x+7 and putting it in the first one we get: 

5x+x+7-25=0 so 6x - 18=0 

So 6x=18 so x=3.



Then plugging 3 into either one to find y. I will do the bottom one. 

3-2y=7 so 2y=-4 y=-2 :D

Answer 2

5x+2y=(?)-25

x-2y=7

5x+2y=-25

add the two equations

6x=-18

x=-3

substitute

-3-2y=7

-2y=10

y=-5

(-3,-5) is the solution

check:5(-3)+2(-5)=-25

           -15+(-10)=-25

                     -25=-25

-3-2(-5)=7

-3+10=7

       7=7