Answer:
[tex]a = - 7[/tex]
[tex]a = - 1[/tex]
Step-by-step explanation:
[tex](a+4) {}^{2} - 3 {}^{2} \\ a {}^{2} + 8a + 16 - 9 \\ a {}^{2} + 8a + 7 \\ a {}^{2} + a + 7a + 7 \\ a(a + 1) + 7(a + 1) \\ (a + 7)(a + 1) \\ a + 7 = 0 \: \: \: \: or \: \: \: \: a + 1 = 0 \\ a = - 7 \: \: \: \: \: \: \: \: or \: \: \: a = - 1[/tex]
