3-(-28)=f

Solution for 3-(-28)=f equation:

Simplifying
3 + -1(-28) = f

Multiply -1 * -28
3 + 28 = f

Combine like terms: 3 + 28 = 31
31 = f

Solving
31 = f

Solving for variable 'f'.

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

Add '-1f' to each side of the equation.
31 + -1f = f + -1f

Combine like terms: f + -1f = 0
31 + -1f = 0

Add '-31' to each side of the equation.
31 + -31 + -1f = 0 + -31

Combine like terms: 31 + -31 = 0
0 + -1f = 0 + -31
-1f = 0 + -31

Combine like terms: 0 + -31 = -31
-1f = -31

Divide each side by '-1'.
f = 31

Simplifying
f = 31