Question

5a + c = -8a Solve the equation for the variable a

Answer 1

$5a+c=-8a \\\\ 5a+8a=-c \\\\ 13a=-c \\\\ \boxed{a=-\frac{c}{13}}$

Answer 2

$5a+c=-8a \\ 5a+c-5a=-8a-5a \\ c=-13a \\ \frac{c}{-13} = \frac{-13a}{-13} \\ -\frac{c}{13} =a$