Question

solve the following quadratic equations by factorisation method: x^2- 5x- 36= 0

Answer 1

$x^{2} - 5x - 36 = 0 \\ {x}^{2} - (9 - 4)x - 36 = 0 \\ {x}^{2} - 9x + 4x - 36 = 0 \\ x(x - 9) + 4(x - 9) = 0 \\ (x + 4)(x - 9) = 0 \\ therefore \\ x = - 4 \: and \: x = + 9$

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