Question

Solve by completing the square and then use the square root method to solve. x2 - 4x - 32 = 0

Answer 1

(x - 2)^2 - 4 - 32 = 0
(x-2)^2 = 36
x-2 = 6 or -6
solution is 8, -4

Answer 2

rewrite the equation

x^2 - 4x = 32

then add (4/2)^2 to both sides

x^2 - 4x + 4 = 32 + 4

factorise

(x-2)^2 = 36

\[x - 2 = \sqrt{36}\]

\[x - 2 = \pm 6\]

\[x = 2 \pm 6\]

x = 2 + 6 x = 2 - 6
= 8 = -4