Alix B. answered 02/09/15
Tutor
New to Wyzant
Hi, Annna.
Let me do a similar problem for you. You can follow along with my work and solve your problem.
Let's say I wanted to find a polynomial with roots 6, 8, and the square root of 7. First, I would start by recognizing that that if the square root of 7 is a root, so is negative square root of 7. Next, I would find the four factors of my polynomial by subtracting each root from x, like this:
(x-6)(x-8)(x-√7)(x--√7)
Because subtracting a negative is like adding a positive, I can simplify a little:
(x-6)(x-8)(x-√7)(x+√7)
Now I need to multiply everything out to get my polynomial in standard form. I'll just "FOIL" the first two factors together and "FOIL" the second two facotrs together to get:
(x2-14x+48)(x2+7)
Now I need to multiply the two factors above. I get:
x4-14x3+55x2-98x+336
I hope this helps! You can do all of the same steps using the numbers in your problem. Good luck!