Show that x squared (sqd) - 4x - 12 = 0
x sqd + (x + 2) sqd = (x + 4) sqd
x sqd + (x + 2) ( x + 2) = (x + 4) (x + 4) times out the brackets
x sqd + x sqd + 4x (2x + 2x) + 4 x sqd + 8x (4x + 4x) + 16
x sqd + 4x + 4 = 8x + 16 take away x sqd
x sqd - 4x + 4 = 16 take away 8x
x sqd - 4x - 12 = 0 take away 16
Solve x sqd - 4x - 12 = 0
(x - 2) sqd - 16 = 0 ~ (x - 2) sqd = 16 ~ x - 2 = sqd root of 16 ~ x = sqd root of 16 + 2 or sqd root of 16 - 2
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