x/x = 1 I think you meant x/ (x+4)<---------- and -----------> (-9/(x+3))
multiply both sides by (x+4)
x = (x+4)(-9/(x+3) ) now multiply both sides by - (1/(x+3)
-x(x+3) = 9x+36
-x^2 -3x = 9x + 36 re-arrange
-x^2 -12x - 36 = 0 or
x^2 + 12x + 36 = 0 factor
(x+6)(x+6) = 0 x = -6 (two roots)