Answer:
[tex]-1,7 \ and \ 1,-7[/tex]
Step-by-step explanation:
let [tex]x[/tex] and [tex]y[/tex] be two other factors.
[tex]Given \ that -3\times x\times y=21\\\Rightarrow xy=\frac{-21}{3} \\xy=-7[/tex]
[tex]7[/tex] is a prime number. Its factors can be [tex]1[/tex] and [tex]7[/tex] only.
But product is negative so one of the number must be negative.
Two cases possible [tex]-1,7[/tex] and [tex]1,-7[/tex].