Question

b) solve by factorisation
$x { }^{2} + x - 72 = 0$
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Answer 1

QUESTION:- SOLVE EQUATION BY FACTORISATION

EQUATION:-

${x}^{2} + x - 72 = 0$

ANSWER:-

${x}^{2} + x - 72 = 0\\{x}^{2} + 9x - 8x - 72 = 0 \\ x(x + 9) - 8(x +9) = 0 \\ (x - 8)(x + 9) = 0$

NOW FOR VALUE OF X ->

$x - 8 = 0 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: x + 9 = 0\\ x = 8 \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: \: x = - 9$