6+3(D-1)=18

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

Simplifying
6 + 3(D + -1) = 18

Reorder the terms:
6 + 3(-1 + D) = 18
6 + (-1 * 3 + D * 3) = 18
6 + (-3 + 3D) = 18

Combine like terms: 6 + -3 = 3
3 + 3D = 18

Solving
3 + 3D = 18

Solving for variable 'D'.

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

Add '-3' to each side of the equation.
3 + -3 + 3D = 18 + -3

Combine like terms: 3 + -3 = 0
0 + 3D = 18 + -3
3D = 18 + -3

Combine like terms: 18 + -3 = 15
3D = 15

Divide each side by '3'.
D = 5

Simplifying
D = 5