Question

The product of 3 rational numbers is 21. If one of those numbers is -3, find two possible factors that make the statement true.

Answer 1

`-1,7 \ and \ 1,-7`

Explanation:

let
`x` and
`y` be two other factors.

`Given \ that -3* x* y=21\\\Rightarrow xy=(-21)/(3) \\xy=-7`

`7` is a prime number. Its factors can be
`1` and
`7` only.

But product is negative so one of the number must be negative.

Two cases possible
`-1,7` and
`1,-7`.