Answer:
p(x) = (x + 3) (2x + 1) (x − 4)
Step-by-step explanation:
One way to find the other factor is long division (see attached).
Another way is to multiply x + 3 by ax² + bx + c, then match the result to p(x).
(x + 3) (ax² + bx + c)
ax³ + bx² + cx + 3ax² + 3bx + 3c
ax³ + (b+3a)x² + (c+3b)x + 3c
a = 2, b = -7, c = -4
Therefore:
p(x) = (x + 3) (2x² − 7x − 4)
Factoring:
p(x) = (x + 3) (2x + 1) (x − 4)
