Conditia de existenta :x≥0
[tex][(1+\sqrt{x})^{1/3}+(1-\sqrt{x})^{1/3}]^3=2^3 \\
1+ \sqrt{x} +1- \sqrt{x} +3 \sqrt[3]{(1+ \sqrt{x} )(1- \sqrt{x} )} *2=8 \\
6\sqrt[3]{(1+ \sqrt{x} )(1- \sqrt{x} )} =6 \\
\sqrt[3]{1-x } =1 \\
1-x=1 \\
x=0[/tex]
Am folosit:(a+b)³=a³+b³+3ab(a+b).
