Answer:Simplifying
3d + -4d = 1.2
Combine like terms: 3d + -4d = -1d
-1d = 1.2
Solving
-1d = 1.2
Solving for variable 'd'.
Move all terms containing d to the left, all other terms to the right.
Divide each side by '-1'.
d = -1.2
Simplifying
d = -1.2
Explanation: