Answer:
(3 - x)(3 + x)(2x + 1)
Step-by-step explanation:
18x - 2x³ + 9 - x² ( factor the first/second and third/fourth terms )
= 2x(9 - x²) + 1 (9 - x²) ← factor out (9 - x²) from each term
= (9 - x²(2x + 1) ← 9 - x² is a difference of squares a² - b² = (a - b)(a + b) )
= (3² - x²)(2x + 1)
= (3 - x)(3 + x)(2x + 1)
