PSAT #1, Section 3, #17

If x-2 is a factor of x^2-bx+b, then you know that for some other factor x-a,


The equivalent polynomials rule tells you that in this case, 2a=b and -2x-ax=-bx. Simplify that second one a bit and you get 2+a=b. You might just see the answer at this point, but you can also solve the system by substituting for b:


If a=2, then b=4.

Leave a Reply