Chapter 8 - Polynomials and Factoring - 8-5 Factoring X(squared) + bx + c - Practice and Problem-Solving Exercises - Page 503: 30

(d-9)(d+2)

Given the polynomial $d^{2}$ - 7d - 18 *** We break of the middle term into two factors that add to give -7 and multiply to give -18. The two numbers are -9 and +2. $d^{2}$ - 9d + 2d - 18 We take the GCD of the first two and the GDC of the last two terms. d(d-9) +2(d-9) We take (d-9) and factor it out which gives us. (d-9)(d+2)