Question

How do you factor by grouping `xy + x - y - 1`?

Answer 1

`xy + x - y -1`

We factor this expression by making groups of 2 terms
`= (xy + x) + (-y -1)`

Now we take the common factors out from each group
`= x( y+ 1) - 1(y+1)`

`( y+1)` is a common factor to each of the terms now:
`= (y+1)(x-1)`

`color(green)((y+1)(x-1))` is the Factorised form of `xy + x - y -1`