slope-intercept form looks like this: y = mx + b (m is the slope value).
As you can see from the slope-intercept form, the "y" needs to be on a side alone, so move all other values to the other side.
-5y = -2x - 15 --> Not, divide the -5 off the "y".
y = 2/5x + 3
Therefore, your equation in slope-intercept form is y = 2/5x + 3