Question

Factorise - x² - 21x + 108​

Answer 1

AnsweR :

$\sf \tt \large {x}^{2} - 21x + 108 \\ \\ \tt= {x}^{2} - 9x - 12x + 108 \\ \\ \tt = x(x - 9) - 12(x - 9) \\ \\ \tt = (x - 12)(x - 9)$

Answer 2

${x}^{2} - 21x + 108$

${x}^{2} - 12x - 9x + 108$

$x(x - 12) - 9(x - 12)$

$(x - 9)(x - 12)$

$x = 9 \: or \: x = 12$

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