Thread: Algebra II

Find the number a such that x-1 is a factor of x^3+ax^2-x+8

Use the polynomial remainder theorem.

Also, you could use Vieta's theorem.

When you have: , you know that:







... where are roots of .

So when you have and you know that 1 is root ( ), you can write three equations:







... so you have 3 equations with three unknowns, and you can solve for .

Well, if you really want to do it the hard way! Personally I would prefer to evaluate the polynomial at x= 1.

Thanks guys that was a huge help!!