Answer:
(z + 8)(z + 9)
Step-by-step explanation:
To factorise the quadratic
Consider the factors of the constant term ( + 72) which sum to give the coefficient of the z- term ( + 17)
The factors are + 8 and + 9
since 8 × 9 = 72 and 8 + 9 = 17, hence
z² + 17z + 72 = (z + 8)(z + 9) ← in factored form
