solving the system of linear equations

Question

1/5x +1/7y=1

1/4x-1/2y=1

Answer 1

20(1/5x +1/7y=1) 4x + (20/7)y = 20

16(1/4x-1/2y=1) -(4x - 8y = 16)

(20/7)y - 8y = 4

(20/7)y - (56/7)y = 4

(-36/7)y = 4

-36y = 28

y = -28/36 = -14/18 = -7/9

you can finish by plugging this y value back into one of these equations to solve for x