4=0.4[3d-5]

Solution for 4=0.4[3d-5] equation:

Simplifying
4 = 0.4[3d + -5]

Reorder the terms:
4 = 0.4[-5 + 3d]
4 = [-5 * 0.4 + 3d * 0.4]
4 = [-2 + 1.2d]

Solving
4 = -2 + 1.2d

Solving for variable 'd'.

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

Add '-1.2d' to each side of the equation.
4 + -1.2d = -2 + 1.2d + -1.2d

Combine like terms: 1.2d + -1.2d = 0.0
4 + -1.2d = -2 + 0.0
4 + -1.2d = -2

Add '-4' to each side of the equation.
4 + -4 + -1.2d = -2 + -4

Combine like terms: 4 + -4 = 0
0 + -1.2d = -2 + -4
-1.2d = -2 + -4

Combine like terms: -2 + -4 = -6
-1.2d = -6

Divide each side by '-1.2'.
d = 5

Simplifying
d = 5