times by a on both sides
a(a+8)= -5
expand brackets
a^2 + 8a = -5
minus 5 on both sides to set equal to 0
a^2 + 8a -5 = 0
use quadratic formula to get 2 solutions
-
[tex] \frac{ - (8) + or - \sqrt{ {8}^{2} - 4(1)(5) } }{2(1)} [/tex]
type into calculator. one solution from + other from -