Question

X^4 - x^3 - 20x^2 =0

Answer 1

Solve by factoring;

$\begin{gathered} x^4-x^3-20x^2=0 \\ \text{Note that x}^2\text{ is a common factor, therefore} \\ x^2(x^2-x-20)=0 \\ \text{This means,} \\ x^2=0 \\ OR \\ x^2-x-20=0 \\ \text{Solve the quadratic equation and you'll have} \\ (x+4)(x-5)=0 \\ \text{Hence,} \\ x+4=0, \\ x-5=0 \\ x=-4, \\ x=5 \end{gathered}$

For the equation given, the factors are

x = 0, x = -4, x = 5