.3=0.2(c-1)

Solution for .3=0.2(c-1) equation:

Simplifying
0.3 = 0.2(c + -1)

Reorder the terms:
0.3 = 0.2(-1 + c)
0.3 = (-1 * 0.2 + c * 0.2)
0.3 = (-0.2 + 0.2c)

Solving
0.3 = -0.2 + 0.2c

Solving for variable 'c'.

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

Add '-0.2c' to each side of the equation.
0.3 + -0.2c = -0.2 + 0.2c + -0.2c

Combine like terms: 0.2c + -0.2c = 0.0
0.3 + -0.2c = -0.2 + 0.0
0.3 + -0.2c = -0.2

Add '-0.3' to each side of the equation.
0.3 + -0.3 + -0.2c = -0.2 + -0.3

Combine like terms: 0.3 + -0.3 = 0.0
0.0 + -0.2c = -0.2 + -0.3
-0.2c = -0.2 + -0.3

Combine like terms: -0.2 + -0.3 = -0.5
-0.2c = -0.5

Divide each side by '-0.2'.
c = 2.5

Simplifying
c = 2.5