Answer:
(9p + 9q - 8)(p + q + 1)
Explanation:
Treat p + q as x. Then this is a quadratic trinomial in x.
9(p + q)² + (p + q) - 8 =
= [9(p + q) - 8][(p + q) + 1]
= (9p + 9q - 8)(p + q + 1)
It may be easier for you to see it if you actually make a substitution:
Let x = p + q.
9(p + q)² + (p + q) - 8 =
Let x = p + q.
= 9x² + x - 8
Now factor the quadratic trinomial.
= (9x - 8)(x + 1)
Now substitute back p + q for x.
= [9(p + q) - 8][p + q + 1)
= (9p + 9q - 8)(p + q + 1)