-(f+1)+6(f-9)=-80

Solution for -(f+1)+6(f-9)=-80 equation:

Simplifying
-1(f + 1) + 6(f + -9) = -80

Reorder the terms:
-1(1 + f) + 6(f + -9) = -80
(1 * -1 + f * -1) + 6(f + -9) = -80
(-1 + -1f) + 6(f + -9) = -80

Reorder the terms:
-1 + -1f + 6(-9 + f) = -80
-1 + -1f + (-9 * 6 + f * 6) = -80
-1 + -1f + (-54 + 6f) = -80

Reorder the terms:
-1 + -54 + -1f + 6f = -80

Combine like terms: -1 + -54 = -55
-55 + -1f + 6f = -80

Combine like terms: -1f + 6f = 5f
-55 + 5f = -80

Solving
-55 + 5f = -80

Solving for variable 'f'.

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

Add '55' to each side of the equation.
-55 + 55 + 5f = -80 + 55

Combine like terms: -55 + 55 = 0
0 + 5f = -80 + 55
5f = -80 + 55

Combine like terms: -80 + 55 = -25
5f = -25

Divide each side by '5'.
f = -5

Simplifying
f = -5