f4 maths 緊急!!!

Let the roots are α and β

Then αβ = 12. As α and β are integers, they are the factors of 12

So, pairs of α and β are

(-1,-12), (-2,-6), (-3,-4), (1,12), (2,6), (3,4)

Also, a = α + β

So, possible values of a are -13, -8, -7, 7, 8, 13