You can use the remainder theorem, which states that if f(x) is divided by x-a, and the remainder is b, then f(a) = b.
In your case,
Solve for k
I'm absolutely stumped by this problem:
If f(x) = (x + 5) (x - k) and the remainder is 28 when f(x) is divided by x - 2, find k.
I figure that I'm supposed to use synthetic division and then have the remainder equal 28, but that isn't getting me the right answer (which is k = -2). Could someone please help me out?