giải pt: x.\sqrt[3]{35-x^{3}}.(x+\sqrt[3]{35-x^{3}})=30 x.\sqrt[3]{35-x^{3}}.(x+\sqrt[3]{35-x^{3}})=30 x.\sqrt[3]{35-x^{3}}.(x+\sqrt[3]{35-x^{3}})=30