Question

Is x^2-9x+8 prime ?

Answer 1

Have you met the Discriminant?

Answer 2

No

Answer 3

Well, then, what methods have you for determining such things?

Answer 4

Factorization!?

Answer 5

x^2-9x+8
Find a number which when adding or subracting is -9 and when multiplying is 8|
So,
x^2-8x-x+8
x(x-8)-1(x-8)
(x-8)(x-1)