Question

Solve $x^2$ + 8𝒙 - 48 = 0 by completing the square method. ( 2 marks)

Answer 1

Step 1:

Completing the square method:

$x^2$+ 8x - 48 = 0

⇒$x^2$ + 8x +16 -16- 48 = 0 ( 1 mark)

Step 2:

$x^2$ +2×x×4+ $4^2$-64=0

⇒${(x+4)}^2$=64

⇒${(x+4)}^2$=$8^2$

⇒x+4=8 or x+4=-8

⇒x=4 or x=-12 ( 1 mark)