Question

cd: factor by gcf and grouping
factor the polynomial by grouping.
$9x^2 - 9x - x + 1$
a $(x - 1)(9x + 1)$
b $(x + 1)(9x + 1)$
c $(x + 1)(9x - 1)$
d $(x - 1)(9x - 1)$

Explanation:

Step1: Group the terms

Group the first two terms and the last two terms: $(9x^2 - 9x) + (-x + 1)$

Step2: Factor out GCF from each group

Factor out $9x$ from the first group and $-1$ from the second group: $9x(x - 1) - 1(x - 1)$

Step3: Factor out the common binomial factor

Factor out $(x - 1)$: $(x - 1)(9x - 1)$

Answer:

D. $(x - 1)(9x - 1)$