Question

Which of the following is a polynomial with roots -sqrt5, sqrt 5, and 3?
A. X^3-2x^2-3x+6
B. X^3+2x^2-3x-6
C. X^3-3x^2-5x+15
D. X^3+3x-5x-15

Answer 1

for this type of problem, it's best to just plug in the answers. it's a waste of time to try to solve 4 different polynomials when they've already given you roots to check

Answer 2

the answer is c. All i did was chose the number 3 to plug into each polynomial first, and fortunately, c was the only answer which satisfied x^3-3x^2-5x+15=0

Answer 3

Yeah I got I worked it out thanks though

Answer 4

no problem :)