3(1.2d-1)+3.6=4.2

Solution for 3(1.2d-1)+3.6=4.2 equation:

Simplifying
3(1.2d + -1) + 3.6 = 4.2

Reorder the terms:
3(-1 + 1.2d) + 3.6 = 4.2
(-1 * 3 + 1.2d * 3) + 3.6 = 4.2
(-3 + 3.6d) + 3.6 = 4.2

Reorder the terms:
-3 + 3.6 + 3.6d = 4.2

Combine like terms: -3 + 3.6 = 0.6
0.6 + 3.6d = 4.2

Solving
0.6 + 3.6d = 4.2

Solving for variable 'd'.

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

Add '-0.6' to each side of the equation.
0.6 + -0.6 + 3.6d = 4.2 + -0.6

Combine like terms: 0.6 + -0.6 = 0.0
0.0 + 3.6d = 4.2 + -0.6
3.6d = 4.2 + -0.6

Combine like terms: 4.2 + -0.6 = 3.6
3.6d = 3.6

Divide each side by '3.6'.
d = 1

Simplifying
d = 1