Answer:
(x + 9)(x - 8)
Explanation:
Factorising the expression
x² + x - 72
consider the factors of the constant term (- 72) which sum to give the coefficient of the x- term (+ 1)
the factors are + 9 and - 8 , since
9 × - 8 = - 72 and 9 - 8 = + 1 , then
x² + x - 72 = (x + 9)(x - 8) ← in factored form