-2(2f-4) = -4(-f+2)
Distribute the -2, multiplying it to each term inside the parentheses.
(-2 × 2f = -4f, and -2 × -4 = 8 because the double negatives cancel)
-4f+8 = -4(-f+2)
Now distribute the -4...
(-4 × -f = 4f, and -4 × 2 = -8)
-4f+8 = 4f-8
Add 4f to each side so that our variable is on just one side of the equation.
8 = 8f-8
To get rid of that -8 and isolate our variable, add 8 to each side.
16 = 8f
Divide each side by 8 to get the value of f.
2 = f