When you think of slope intercept form we think of Y=mx+b
m=slope and b = intercept
So all you do is solve for Y in your given equation.
Im going to guess the equal sign because you didn't include it. I can fix the answer is I was wrong.
3y-15=6x (add 15 to both sides)
3y=6x+15 (divide by 3)
y=2x+3 (final answer)