2(a+3(a-1))=18

Solution for 2(a+3(a-1))=18 equation:

Simplifying
2(a + 3(a + -1)) = 18

Reorder the terms:
2(a + 3(-1 + a)) = 18
2(a + (-1 * 3 + a * 3)) = 18
2(a + (-3 + 3a)) = 18

Reorder the terms:
2(-3 + a + 3a) = 18

Combine like terms: a + 3a = 4a
2(-3 + 4a) = 18
(-3 * 2 + 4a * 2) = 18
(-6 + 8a) = 18

Solving
-6 + 8a = 18

Solving for variable 'a'.

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

Add '6' to each side of the equation.
-6 + 6 + 8a = 18 + 6

Combine like terms: -6 + 6 = 0
0 + 8a = 18 + 6
8a = 18 + 6

Combine like terms: 18 + 6 = 24
8a = 24

Divide each side by '8'.
a = 3

Simplifying
a = 3