-42=-0.75(f+-4)

Solution for -42=-0.75(f+-4) equation:

Simplifying
-42 = -0.75(f + -4)

Reorder the terms:
-42 = -0.75(-4 + f)
-42 = (-4 * -0.75 + f * -0.75)
-42 = (3 + -0.75f)

Solving
-42 = 3 + -0.75f

Solving for variable 'f'.

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

Add '0.75f' to each side of the equation.
-42 + 0.75f = 3 + -0.75f + 0.75f

Combine like terms: -0.75f + 0.75f = 0.00
-42 + 0.75f = 3 + 0.00
-42 + 0.75f = 3

Add '42' to each side of the equation.
-42 + 42 + 0.75f = 3 + 42

Combine like terms: -42 + 42 = 0
0 + 0.75f = 3 + 42
0.75f = 3 + 42

Combine like terms: 3 + 42 = 45
0.75f = 45

Divide each side by '0.75'.
f = 60

Simplifying
f = 60