8a+13+21=0

Solution for 8a+13+21=0 equation:

Simplifying
8a + 13 + 21 = 0

Reorder the terms:
13 + 21 + 8a = 0

Combine like terms: 13 + 21 = 34
34 + 8a = 0

Solving
34 + 8a = 0

Solving for variable 'a'.

Move all terms containing a to the left, all other terms to the right.

Add '-34' to each side of the equation.
34 + -34 + 8a = 0 + -34

Combine like terms: 34 + -34 = 0
0 + 8a = 0 + -34
8a = 0 + -34

Combine like terms: 0 + -34 = -34
8a = -34

Divide each side by '8'.
a = -4.25

Simplifying
a = -4.25