it all depends on which exponent your trying to find.
if your trying to find x. then it would go like this; y=mx+b
y= 3x-2
y+2=3x-2+2(what you do to one side, you must do to the other)
2y/3=3x/3
0.66=x
y-exponent.
y=mx+b
y=3x-2
y-3x+y=3x-2-3x+y
3x=-2+y
3x+2=-2+y+2
3x/x+2/x=y
3+2=y
5=y
i hope this helps! im not 100% right this is right. but im almost sure.