Question

How do you factor `y=x^2 - 4x - 21`?

Answer 1

`(x-7)(x+3)`

Explanation:

Find factors of 21 which subtract to make 4.

Signs will be different, with more negatives.,

`7 xx3 = 21 " " 7 - 3 = 4`

`(x-7)(x+3)`