Question

Locating Zeros of Polynomial Function:

Approximate the real zeros of f(x)=x^3-4x+6 to the nearest tenth

Answer 1

Answer: D or -2.5

Explanation:

By using a graphing calculator, we can see that there is only one rational x intercept, -2.525. By simply rounding this value to the nearest tenth we get -2.5

Answer 2

-2.5 is the best approximation. Putting this into the equation we get:

-2.5*-2.5*-2.5 -4*-2.5 +6

-15.625 + 10 + 6 = .375