12=3(3a+1)

Solution for 12=3(3a+1) equation:

Simplifying
12 = 3(3a + 1)

Reorder the terms:
12 = 3(1 + 3a)
12 = (1 * 3 + 3a * 3)
12 = (3 + 9a)

Solving
12 = 3 + 9a

Solving for variable 'a'.

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

Add '-9a' to each side of the equation.
12 + -9a = 3 + 9a + -9a

Combine like terms: 9a + -9a = 0
12 + -9a = 3 + 0
12 + -9a = 3

Add '-12' to each side of the equation.
12 + -12 + -9a = 3 + -12

Combine like terms: 12 + -12 = 0
0 + -9a = 3 + -12
-9a = 3 + -12

Combine like terms: 3 + -12 = -9
-9a = -9

Divide each side by '-9'.
a = 1

Simplifying
a = 1