Question
$$x^4+5x^6 = 20\cdot20$$
Answer
This equation has no solution.
Explanation
$$ \begin{aligned} x^4+5x^6 &= 20\cdot20&& \text{simplify left and right hand side} \\[1 em]5x^6+x^4 &= 400&& \text{move all terms to the left hand side } \\[1 em]5x^6+x^4-400 &= 0&& \\[1 em] \end{aligned} $$
This polynomial has no rational roots that can be found using Rational Root Test.
Roots were found using Newton method.
This page was created using
Polynomial Equations Solver