Try every possible combination you can find. Either one of them will work or none of them will work. Factors of 10 are 1 & 10, and 2 & 5. Factors of 20 are 1 & 20, 2 & 10, 4 & 5.
(x 1)(10x 20)
(x 20)(10x 1)
(x 2)(10x 10)
(x 10)(10x 2)
and several more different combinations to check...
You might get tired doing that way but you will find what you need.
Discriminant,
Yours is
--------not a perfect square
Your quadratic expression is not factorable into integer coefficients. Not rational coefficients either.
...