21a+6=18a-6

Solution for 21a+6=18a-6 equation:

Simplifying
21a + 6 = 18a + -6

Reorder the terms:
6 + 21a = 18a + -6

Reorder the terms:
6 + 21a = -6 + 18a

Solving
6 + 21a = -6 + 18a

Solving for variable 'a'.

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

Add '-18a' to each side of the equation.
6 + 21a + -18a = -6 + 18a + -18a

Combine like terms: 21a + -18a = 3a
6 + 3a = -6 + 18a + -18a

Combine like terms: 18a + -18a = 0
6 + 3a = -6 + 0
6 + 3a = -6

Add '-6' to each side of the equation.
6 + -6 + 3a = -6 + -6

Combine like terms: 6 + -6 = 0
0 + 3a = -6 + -6
3a = -6 + -6

Combine like terms: -6 + -6 = -12
3a = -12

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

Simplifying
a = -4