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x^{3}-3x-2=0
Subtract 2 from both sides.
±2,±1
By Rational Root Theorem, all rational roots of a polynomial are in the form \frac{p}{q}, where p divides the constant term -2 and q divides the leading coefficient 1. List all candidates \frac{p}{q}.
x=-1
Find one such root by trying out all the integer values, starting from the smallest by absolute value. If no integer roots are found, try out fractions.
x^{2}-x-2=0
By Factor theorem, x-k is a factor of the polynomial for each root k. Divide x^{3}-3x-2 by x+1 to get x^{2}-x-2. Solve the equation where the result equals to 0.
x=\frac{-\left(-1\right)±\sqrt{\left(-1\right)^{2}-4\times 1\left(-2\right)}}{2}
All equations of the form ax^{2}+bx+c=0 can be solved using the quadratic formula: \frac{-b±\sqrt{b^{2}-4ac}}{2a}. Substitute 1 for a, -1 for b, and -2 for c in the quadratic formula.
x=\frac{1±3}{2}
Do the calculations.
x=-1 x=2
Solve the equation x^{2}-x-2=0 when ± is plus and when ± is minus.
x=-1 x=2
List all found solutions.