For the polynomial equation 3x3−x2−7x+8, how do you determine all possible rational roots?
1 Answer
Mar 16, 2017
The only "possible" rational zeros are:
±13,±23,±1,±43,±2,±83,±4,±8
Explanation:
Given:
3x3−x2−7x+8
By the rational root theorem, any rational zeros of this cubic are expressible in the form
That means that the only possible rational zeros are:
±13,±23,±1,±43,±2,±83,±4,±8
In fact, none of these work, so this cubic only has irrational and/or complex zeros. Its only real zero is approximately
graph{3x^3-x^2-7x+8 [-5, 5, -2.52, 15]}
