(w+6)(w+7) = 0
w(w) + w(7) + 6(w) + 6(7) = 0
w² + 7w + 6w + 42 = 0
w² + 13w + 42 = 0
w + 6 = 0
w = -6
w² + 13w + 42 = 0
-6² + 13(-6) + 42 = 0
36 - 78 + 42 =
78 - 78 = 0
0 = 0
w + 7 = 0
w = -7
w² + 13w + 42 = 0
-7² + 13(-7) + 42 = 0
49 - 91 + 42 = 0
91-91 = 0
0=0
