Question

How do you factor `p^2- 19p - 42 = 0`?

Answer 1

You only asked for the factorisation!

`(p+2)(p-21)=0`
`p=-2" and/or "p=+21`

Explanation:

Notice that `2xx21=42" and "-21+2=-19`

So we have:

`(p+2)(p-21)=0`

Thus for the above to be true `p` has to have one of the two solutions:

`p=-2" and/or "p=+21`