How to solve this system by the elimination and substitution method?

[Lisa Marie]

Elimination;
9-6g=f
-6g+3f=15
and
2x+3y=0
-x-3y=3

Substitution;
y=4x+5
4x-y=-5
and
y+3x=0
2y-5=-x
Please Explain, and Thanks!