Question

factorize
9a^2-12a-21

plz help me out fast

Answer 1

Step-by-step explanation:

hope it will help you............

Answer 2

Answer:

$9 {a}^{2} - 12a - 21 = 0 \\ 3(3 {a}^{2} - 4a - 7) = 0 \\ 3 {a}^{2} + 3a - 7a - 7 = 0 \\ 3a(a + 1) - 7(a + 1) = 0 \\ 3a - 7 = 0 \: \: \: \: \: \: \: \: a + 1 = 0 \\ a = \frac{7}{3} \: \: \: \: \: \: \: \: \: \: a = - 1$