Oops sorry for the late reply.

The slope-intercept form of a linear equation is y=mx+b

This means you have to isolate the dependent variable (y)

To do that you first multiple the 3 into (x+2) which will get you 3x+6

So you would have 3x + 6 = y - 7

Then to isolate "y" just add 7 to both sides.

3x + 6 + 7 = y - 7 + 7

Solving both sides will get you 3x + 13 = y or y = 3x + 13 which is the equation in slope-intercept form.