solve system through elimination

Question

-5x+7y=11

-5x+3y=19

 

multiply bottom equation by -1

 

-5x+7y=11

5x-3y= -19

 4y=-8

y=-4

 

-5 (-4) +7y=11

20 + 7y= 11

-20

7y= -9

/7= -9/7

y=-9/7

 

Is this correct (-4, -9/7)?  I don't think it checks out!  :(

Answer 1

4y=-8

y=-8/4=-2

so, y=-2

 

plug this in for y

-5x + 7(-2) = 11

-5x -14 = 11

-5x = 11 + 14

-5x = 25

x = 25/-5

x = -5