I would use slope-intercept form. I always think it's the easiest.
Slope intercept form looks like this y=mx+b
m is your slope and b is your y-intercept (which you're looking for)
So you have to go from 5x+2y=5 and put it into the y=mx+b form.
In other words, solve for y.
Step 1) Subtract 5x from both sides.
5x+2y=5 ----> 2y=5-5x
Step 2) Divide both sides by two (then y will be alone, but remember to divide everything on the other side by two!)
2y=5-5x -----> y= (5-5x) / 2 -------> y=(5/2) - (5/2)x
Step 3) Rewrite it so it's mx+b
(5/2) - (5/2)x ----> -(5/2)x + (5/2)
Remember, you're looking for b (the y-intercept) so it's simply 5/2
Hope this helps and good luck in class.