12+10+5=a^2-9

Solution for 12+10+5=a^2-9 equation:

Simplifying
12 + 10 + 5 = a2 + -9

Combine like terms: 12 + 10 = 22
22 + 5 = a2 + -9

Combine like terms: 22 + 5 = 27
27 = a2 + -9

Reorder the terms:
27 = -9 + a2

Solving
27 = -9 + a2

Solving for variable 'a'.

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

Add '-1a2' to each side of the equation.
27 + -1a2 = -9 + a2 + -1a2

Combine like terms: a2 + -1a2 = 0
27 + -1a2 = -9 + 0
27 + -1a2 = -9

Add '-27' to each side of the equation.
27 + -27 + -1a2 = -9 + -27

Combine like terms: 27 + -27 = 0
0 + -1a2 = -9 + -27
-1a2 = -9 + -27

Combine like terms: -9 + -27 = -36
-1a2 = -36

Divide each side by '-1'.
a2 = 36

Simplifying
a2 = 36

Take the square root of each side:
a = {-6, 6}