Elimination is something like this:
y= 3x + 20
y=-3x + 4
=================
y= (take away the x's because you are adding both equations basically) 24
substitution:
y=25
50=25+ y
this might be a bad equation example but you take the y from the top equation and substitute it making the 2nd equation now:
50=25 + (25)
50=50
then you do the problem from there
graphing..... I can't help with that, sorry! But I hoped I helped!