Question

Complete the following activity to solve the given quadratic equation by factorization method.

Activity: x² + 8x – 20 = 0

x² + ( __ ) – 2x – 20 = 0

x (x + 10) – ( __ ) (x + 10) = 0

(x + 10) ( ____ ) = 0

x = ___ or x = 2

Answer 1

x² + 8x – 20 = 0

x² + 10x – 2x – 20 = 0

∴ x (x + 10) – 2 (x + 10) = 0

∴ x (x + 10) – (x – 2) = 0

∴ x + 10 = 0 or x – 2 = 0

x = – 10 or x = 2