so it's like 'which one of the number given is a factor of, say, 10' and the choices are 4,5,7,9. the answer is 5 so just factor out the equation
the factored out form is
factor out the 3x^2 and get
(3x^2)(3x^2-2x+1)
and 3x^2-2x+1 is the fourth choice