Question

Factorize:
x² - 21x + 90

Answer 1

x² - 21x + 90

= x² - 15x - 6x + 90

= x(x - 15) - 6(x - 15)

= (x - 6)(x - 15).

Answer 2

Step-by-step explanation:

We Have :-

$x^{2} - 21x + 90$

To Find :-

$factors$

Method Used :-

$middle \: term \: splitting$

Solution :-

$x^{2} - 21x + 90 \\ \\ \\ x^{2} - 21x + 90 = 0 \\ \\ \\ x^{2} - 15x - 6x + 90 = 0 \\ \\ \\ x(x - 15) - 6(x - 15) = 0 \\ \\ \\ (x - 15)(x - 6) =0 \\ \\ \\ so \: \\ \\ \\ x - 15 = 0 \\ \\ \\ x = 15 \\ \\ \\ x - 6 = 0 \\ \\ \\ x = 6 \\ \\ \\ so \: the \: factors \: are \: 6 \: and \: 15$