(a) x² + 5x + 4 = 0, is factorized as (x + 4)(x + 1) = 0.
(b) x² + 5x + 6 = 0, is factorized as (x + 2)(x + 3) = 0.
(c). x² + 7x + 6 = 0, this is factorized as (x + 6)(x + 1) = 0.
(d) x² + 10x + 16 = 0, this is factorized as (x + 2)(x + 8) = 0
(e), x² + 10x + 21 = 0, this is factorized as (x + 7)(x + 3) = 0.
How to solve the quadratic equation?
The solution of the quadratic equation by factorization method is determined as follows.
(a) x² + 5x + 4 = 0, is factorized as;
x² + 5x + 4 = 0
x² + x + 4x + 4 = 0
x(x + 1) + 4(x + 1) = 0
(x + 4)(x + 1) = 0
(b) x² + 5x + 6 = 0, is factorized as;
x² + 5x + 6 = 0
x² + 2x + 3x + 6 = 0
x(x + 2) + 3(x + 2) = 0
(x + 2)(x + 3) = 0
(c). x² + 7x + 6 = 0, this is factorized as;
x² + 7x + 6 = 0
x² + x + 6x + 6 = 0
x (x + 1) + 6(x + 1) = 0
(x + 6)(x + 1) = 0
(d) x² + 10x + 16 = 0, this is factorized as;
x² + 10x + 16 = 0
x² + 2x + 8x + 16 = 0
x(x + 2) + 8(x + 2) = 0
(x + 2)(x + 8) = 0
(e), x² + 10x + 21 = 0, this is factorized as;
x² + 10x + 21 = 0
x² + 3x + 7x + 21 = 0
x( x + 3) + 7 (x + 3) = 0
(x + 7)(x + 3) = 0