-3+15=-a+5a

Solution for -3+15=-a+5a equation:

Simplifying
-3 + 15 = -1a + 5a

Combine like terms: -3 + 15 = 12
12 = -1a + 5a

Combine like terms: -1a + 5a = 4a
12 = 4a

Solving
12 = 4a

Solving for variable 'a'.

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

Add '-4a' to each side of the equation.
12 + -4a = 4a + -4a

Combine like terms: 4a + -4a = 0
12 + -4a = 0

Add '-12' to each side of the equation.
12 + -12 + -4a = 0 + -12

Combine like terms: 12 + -12 = 0
0 + -4a = 0 + -12
-4a = 0 + -12

Combine like terms: 0 + -12 = -12
-4a = -12

Divide each side by '-4'.
a = 3

Simplifying
a = 3