2[d+3(d+1)]=18

Solution for 2[d+3(d+1)]=18 equation:

Simplifying
2[d + 3(d + 1)] = 18

Reorder the terms:
2[d + 3(1 + d)] = 18
2[d + (1 * 3 + d * 3)] = 18
2[d + (3 + 3d)] = 18

Reorder the terms:
2[3 + d + 3d] = 18

Combine like terms: d + 3d = 4d
2[3 + 4d] = 18
[3 * 2 + 4d * 2] = 18
[6 + 8d] = 18

Solving
6 + 8d = 18

Solving for variable 'd'.

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

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

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

Combine like terms: 18 + -6 = 12
8d = 12

Divide each side by '8'.
d = 1.5

Simplifying
d = 1.5