-7x - 3y = -6 -3x + 7y = 14

-7x - 3y = -6    ...(1)

-3x + 7y = 14   ...(2)

 

Multiply through (1) by 7 and (2) by 3

-49x - 21y = -42    ...(3)

-9x + 21y  = 42     ...(4)

 

Add (3) and (4) term by term

-58x = 0

x = 0

Put this in (1)

-7*0 - 3y = -6

-3y = -6

y = 2