Answer:
Step-by-step explanation:
[tex]4x^{\frac{3}{2} } +5=21\\4x^{\frac{3}{2} =21-5} \\x^{\frac{3}{2} } =\frac{16}{4} =4\\squaring\\x^{3} =4^2=16\\x=\sqrt[3]{16}[/tex]
