#### Answer

$x\sqrt[4]{x}$

#### Work Step by Step

Using the definition of rational exponents which is given by $a^{\frac{m}{n}}=\sqrt[n]{a^m}=\left(\sqrt[n]{a}\right)^m,$ the given expression is equivalent to
\begin{array}{l}\require{cancel}
\sqrt[4]{x^3}\sqrt{x}
\\\\=
x^{3/4}\cdot x^{1/2}
.\end{array}
Using the Product Rule of the laws of exponents which is given by $x^m\cdot x^n=x^{m+n},$ the expression above is equivalent to
\begin{array}{l}\require{cancel}
x^{3/4}\cdot x^{1/2}
\\\\=
x^{\frac{3}{4}+\frac{1}{2}}
\\\\=
x^{\frac{3}{4}+\frac{2}{4}}
\\\\=
x^{\frac{5}{4}}
.\end{array}
Using the definition of rational exponents which is given by $a^{\frac{m}{n}}=\sqrt[n]{a^m}=\left(\sqrt[n]{a}\right)^m,$ the given expression is equivalent to
\begin{array}{l}\require{cancel}
x^{\frac{5}{4}}
\\\\=
\sqrt[4]{x^5}
.\end{array}
Extracting the factors that are perfect powers of the index, the expression above simplifies to
\begin{array}{l}\require{cancel}
\sqrt[4]{x^4\cdot x}
\\\\=
\sqrt[4]{(x)^4\cdot x}
\\\\=
x\sqrt[4]{x}
.\end{array}
Note that all variables are assumed to represent positive numbers.