Answer:
(u + 8)(u + 9)
Explanation:
Assuming you require to factorise the expression
u² + 17u + 72
Consider the factors of the constant term (+ 72) which sum to give the coefficient of the u- term (+ 17)
The factors are + 8 and + 9, since
8 × 9 = 72 and 8 + 9 = 17, then
u² + 17u + 72 = (u + 8)(u + 9) ← in factored form