15=-6+4(d+3)

Solution for 15=-6+4(d+3) equation:

Simplifying
15 = -6 + 4(d + 3)

Reorder the terms:
15 = -6 + 4(3 + d)
15 = -6 + (3 * 4 + d * 4)
15 = -6 + (12 + 4d)

Combine like terms: -6 + 12 = 6
15 = 6 + 4d

Solving
15 = 6 + 4d

Solving for variable 'd'.

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

Add '-4d' to each side of the equation.
15 + -4d = 6 + 4d + -4d

Combine like terms: 4d + -4d = 0
15 + -4d = 6 + 0
15 + -4d = 6

Add '-15' to each side of the equation.
15 + -15 + -4d = 6 + -15

Combine like terms: 15 + -15 = 0
0 + -4d = 6 + -15
-4d = 6 + -15

Combine like terms: 6 + -15 = -9
-4d = -9

Divide each side by '-4'.
d = 2.25

Simplifying
d = 2.25