Question

Factorise
${x}^{2} - x - 72$
​

Answer 1

Answer:

x^2-x-72

x^2-9x-8x-72

x(x-9) 8(x-9)

(x+8) (x-9)

x+8=0

x=-8

x-9=0

x=9

Answer 2

Answer:

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