please can someone help me with this problem. I am doing substitution.

Question

3x + 4y = 0
y = x you have to substituted the y for x

Then the same other problem with different number.
y = x
-6x + 8y = -2

Answer 1

since y = x
in the first equation
3x + 4y = 0
3x + 4(x) = 0
7x = 0
x = 0 , since y=x, y = 0

do the same thing in the second problem.

Answer 2

Thank you Reiny you really help me.