$$\frac{387}{1000}x^3-\frac{144}{1000}x^2+\frac{619}{100}x+\frac{485}{100} = \frac{507}{100}$$
Answer
$$ \begin{matrix}x_1 = 0.03557 & x_2 = 0.16826+3.99431i & x_3 = 0.16826-3.99431i \end{matrix} $$
Explanation
$$ \begin{aligned} \frac{387}{1000}x^3-\frac{144}{1000}x^2+\frac{619}{100}x+\frac{485}{100} &= \frac{507}{100}&& \text{multiply ALL terms by } \color{blue}{ 1000 }. \\[1 em]1000 \cdot \frac{387}{1000}x^3-1000\frac{144}{1000}x^2+1000\frac{619}{100}x+1000\cdot\frac{485}{100} &= 1000\cdot\frac{507}{100}&& \text{cancel out the denominators} \\[1 em]387x^3-144x^2+6190x+4850 &= 5070&& \text{move all terms to the left hand side } \\[1 em]387x^3-144x^2+6190x+4850-5070 &= 0&& \text{simplify left side} \\[1 em]387x^3-144x^2+6190x-220 &= 0&& \\[1 em] \end{aligned} $$
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using qubic formulas.
This page was created using
Polynomial Equations Solver