Sagot :
[tex]x^5=x^3\\
x^5-x^3=0\\
x^3(x^2-1)=0\\
x^3(x-1)(x+1)=0\\
x=0 \vee x=1 \vee x=-1[/tex]
[tex]x^{5}=x^{3}\\
x^{5}-x^{3}=0\\
x^{3}(x^{2}-1)=0\\
x^{3}=0 \ \ \ \ x^{2}-1=0\\
x=0\\\\
\Delta=b^{2}-4ac=-4*1*(-1)=4\\
\sqrt{\Delta}=\sqrt{4}=2\\\\
x_{1}=\frac{-b-\sqrt\Delta}{2a}=\frac{0-2}{2}=-1\\\\
x_{2}=\frac{-b+\sqrt{\Delta}}{2a}=\frac{0+2}{2}=1\\\\
x\in \{-1;0;1\}[/tex]