Question

(a+1)²-9
that answer and solution

Answer 1

Step-by-step explanation:

${ (a + 1)}^{2} - 9 \\ = {a}^{2} + 2 \times a \times 1 + {1}^{2} - 9 \\ = {a}^{2} + 2a + 1 - 9 \\ = {a}^{2} + 2a - 8$

solution

$\\ \\ {a}^{2} + 2a - 8 = 0 \\ = > {a}^{2} + 4a - 2a - 8 = 0 \\ = > a(a + 4) - 2(a + 4) = 0 \\ (a + 4)(a - 2) = 0 \\ (a + 4) = 0 \: \: or \: \: (a - 2) = 0 \\ a = - 4 \: \: or \: \: a = 2$

hence your answer is

${\boxed{a=-4\:or\:a=2}}$