Which is the equation for the line that passes through (-4, -3) and (-2, 3)

First find the slope, m, of the line connecting these two points:

         rise       3-(-3)           6
m = = = = 3
          run       -2-(-4)           2

Next, borrow the coordinates of one of the given point and substitute them, along with this slope, into the "point-slope" formula for a straight line:

y-3 = 3(x-(-2)), or y-3 = 3(x+2).  This is the answer.   If you wish you could solve this for y and obtain an equation in the form y=mx+b.