Find roots of polynomial $$ p(x) = x^3-2x+4x-8 $$
Answer
The roots of polynomial $ p(x) $ are:
$$ \begin{aligned}x_1 &= 1.6702\\[1 em]x_2 &= -0.8351+2.0229i\\[1 em]x_3 &= -0.8351-2.0229i \end{aligned} $$Explanation
Step 1:
Combine like terms:
$$ x^3 \color{blue}{-2x} + \color{blue}{4x} -8 = x^3+ \color{blue}{2x} -8 $$Step 2:
Polynomial $ x^3+2x-8 $ has no rational roots that can be found using Rational Root Test, so the roots were found using qubic formulas.
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