Answer:
(r-3)(r+3)(r+2)
Step-by-step explanation:
To factor the equation, factor by grouping. Group the terms in pairs and factor out a GCF.
r³ + 2r² - 9r - 18
(r³ + 2r²) +(-9r - 18)
r²(r + 2) -9(r + 2)
(r² -9)(r+2)
Factor r² - 9 as a difference of squares.
(r-3)(r+3)(r+2)