12=0.9a

Solution for 12=0.9a equation:

Simplifying
12 = 0.9a

Solving
12 = 0.9a

Solving for variable 'a'.

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

Add '-0.9a' to each side of the equation.
12 + -0.9a = 0.9a + -0.9a

Combine like terms: 0.9a + -0.9a = 0.0
12 + -0.9a = 0.0

Add '-12' to each side of the equation.
12 + -12 + -0.9a = 0.0 + -12

Combine like terms: 12 + -12 = 0
0 + -0.9a = 0.0 + -12
-0.9a = 0.0 + -12

Combine like terms: 0.0 + -12 = -12
-0.9a = -12

Divide each side by '-0.9'.
a = 13.33333333

Simplifying
a = 13.33333333