-18=6(1+3k)+3k

Solution for -18=6(1+3k)+3k equation:

Simplifying
-18 = 6(1 + 3k) + 3k
-18 = (1 * 6 + 3k * 6) + 3k
-18 = (6 + 18k) + 3k

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

Solving
-18 = 6 + 21k

Solving for variable 'k'.

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

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

Combine like terms: 21k + -21k = 0
-18 + -21k = 6 + 0
-18 + -21k = 6

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

Combine like terms: -18 + 18 = 0
0 + -21k = 6 + 18
-21k = 6 + 18

Combine like terms: 6 + 18 = 24
-21k = 24

Divide each side by '-21'.
k = -1.142857143

Simplifying
k = -1.142857143