Question

f(x)=x^4+x^3-12x^2. Find the zeros of the function

Answer 1

See the suggested decision:
x⁴+x³-12x²=0
1) to simplify the left side:
x²(x²+x-12)=0
x²(x+4)(x-3)=0
2) to resolve each of 3 part:
$\left[\begin{array}{ccc}x^2=0\\x+4=0\\x-3=0\end{array}\right \ \ \textless \ =\ \textgreater \ \left[\begin{array}{ccc}x=0\\x=-4\\x=3\end{array}\right$
answer: -4;0;3.