The expression can be rewritten as:

$\displaystyle\frac{{\sqrt{{{7}{x}}}+\sqrt{{{4}\cdot{7}{x}}}}}{\sqrt{{{2}}}}=\frac{{\sqrt{{{7}{x}}}+{2}\sqrt{{{7}{x}}}}}{{\sqrt{{2}}}}=\frac{{{3}\sqrt{{{7}{x}}}}}{{\sqrt{{2}}}}\usepackage{cmbright}\Huge\$

This is not equal to $\displaystyle\frac{{{3}\sqrt{{{7}{x}}}}}{{1}}\usepackage{cmbright}\Huge\$ because $\displaystyle\sqrt{{2}}\usepackage{cmbright}\Huge\$ is not equal to 1.