How is problem solved using elimination?

Question

  2x+5y=-1                                                                      4x+9y=-5

(-8,3)

Answer 1

2x + 5y = -1

4x + 9y = -5

 

let's multiply top equation by -2 and add result to second equation:

 

-4x - 10y = 2

4x + 9y = -5

       -y = -3

 

so y =3, let's plug in y to top equation:

 

2x + 5(3) = -1

 

2x = -1 - 15

 

2x = -16

 

x = -8