8[a+9]=91.2

Solution for 8[a+9]=91.2 equation:

Simplifying
8[a + 9] = 91.2

Reorder the terms:
8[9 + a] = 91.2
[9 * 8 + a * 8] = 91.2
[72 + 8a] = 91.2

Solving
72 + 8a = 91.2

Solving for variable 'a'.

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

Add '-72' to each side of the equation.
72 + -72 + 8a = 91.2 + -72

Combine like terms: 72 + -72 = 0
0 + 8a = 91.2 + -72
8a = 91.2 + -72

Combine like terms: 91.2 + -72 = 19.2
8a = 19.2

Divide each side by '8'.
a = 2.4

Simplifying
a = 2.4