It is convenient to start with the point-slope form and then simplify it to the desired form.
The point-slope form of the equation for a line with slope m through point (h, k) can be written as ...
... y = m(x -h) +k
You have m=-7 and (h, k) = (-3, 16), so you can fill in the numbers to get ...
... y = -7(x +3) +16
... y = -7x -21 +16 . . . eliminate parentheses
... y = -7x -5 . . . . the form you are looking for
