Question

Factorize each of the following quadratic polynomials by using the method of completing:

a² + 2a - 3

Answer 1

a² + 2a – 3

Coefficient of a² = 1

Therefore, we have

a² + 2a – 3 = a² + 2a + 1² – 1² – 3 (Adding and subtracting 1²)

= (a + 1)² – 2² (Completing the square)

= (a + 1 + 2) (a + 1 – 2)

= (a + 3) (a – 1)