99=-6a+3(1+6a)

Solution for 99=-6a+3(1+6a) equation:

Simplifying
99 = -6a + 3(1 + 6a)
99 = -6a + (1 * 3 + 6a * 3)
99 = -6a + (3 + 18a)

Reorder the terms:
99 = 3 + -6a + 18a

Combine like terms: -6a + 18a = 12a
99 = 3 + 12a

Solving
99 = 3 + 12a

Solving for variable 'a'.

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

Add '-12a' to each side of the equation.
99 + -12a = 3 + 12a + -12a

Combine like terms: 12a + -12a = 0
99 + -12a = 3 + 0
99 + -12a = 3

Add '-99' to each side of the equation.
99 + -99 + -12a = 3 + -99

Combine like terms: 99 + -99 = 0
0 + -12a = 3 + -99
-12a = 3 + -99

Combine like terms: 3 + -99 = -96
-12a = -96

Divide each side by '-12'.
a = 8

Simplifying
a = 8