hi

you cannot assume that x=0,because if it isn't it is going to give you wrong answers.

you can try doing something like this:

2x-y=9

-y=9-2x

y=-9+2x

y=2x-9

we substitute into the second equation:

3x+4(2x-9)=-14

3x+8x-36=--14

11x=36-14

11x=22

x=2

can you find y now?