Step-by-step explanation:
[tex] = \sqrt{x} .4 \sqrt{x} [/tex]
[tex] = {x}^{ \frac{1}{2} } \times 4 {x}^{ \frac{1}{2} } [/tex]
[tex] = 4 {x}^{ \frac{1}{2} + \frac{1}{2} } [/tex]
[tex] = 4 {x}^{ \frac{2}{2} } [/tex]
[tex] = 4 {x}^{1} [/tex]
[tex] = 4x[/tex]
