Question

How do you solve for f: `f-1+2f+f-3=-4`?

Answer 1

First of all, let's sum up all terms involving `f` on the left hand, and all numbers as well.

The terms involving `f` are `f+2f+f`, which equals `4f`, while numbers are `-1-3`, which equals `-4`. So far, we can rewrite our equality as
`4f-4=-4`.
Adding 4 on both sides, we get
`4f-4+4=-4+4`, which means
`4f=0`.
Dividing both sides by 4, we have `f=0`.