Solve the system by the method of substitution x + y = 0 and 4x+3y =10

Make both equations equal to x

-y=x

-3/4y+5/2=x

Subsitute:

1/4y=5/2

Multiply by 4:

y=10

i think this could be a possible answer (1 / 84) -1

good luck! : d