we have the expression
[tex]5x\sqrt[]{28x^5}+8x^3\sqrt[]{7x}[/tex]
we know that
28=(2^2)(7)
x^5=(x^4)(x)
substitute in the expression above
[tex]\begin{gathered} 5x\sqrt[]{7\cdot2^2\cdot x^4\cdot x}+8x^3\sqrt[]{7x} \\ \text{Simplify} \\ 5\cdot x\cdot2^{}\cdot x^2\sqrt[]{7\cdot x}+8x^3\sqrt[]{7x} \\ 10x^3\sqrt[]{7x}+8x^3\sqrt[]{7x} \\ 18x^3\sqrt[]{7x} \end{gathered}[/tex]
