.8=.5d-.7d

Solution for .8=.5d-.7d equation:

Simplifying
0.8 = 0.5d + -0.7d

Combine like terms: 0.5d + -0.7d = -0.2d
0.8 = -0.2d

Solving
0.8 = -0.2d

Solving for variable 'd'.

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

Add '0.2d' to each side of the equation.
0.8 + 0.2d = -0.2d + 0.2d

Combine like terms: -0.2d + 0.2d = 0.0
0.8 + 0.2d = 0.0

Add '-0.8' to each side of the equation.
0.8 + -0.8 + 0.2d = 0.0 + -0.8

Combine like terms: 0.8 + -0.8 = 0.0
0.0 + 0.2d = 0.0 + -0.8
0.2d = 0.0 + -0.8

Combine like terms: 0.0 + -0.8 = -0.8
0.2d = -0.8

Divide each side by '0.2'.
d = -4

Simplifying
d = -4