Rationalize the denominator by multiplying the expression by: $\displaystyle\frac{\sqrt{{{a}}}}{\sqrt{{{a}}}}\usepackage{cmbright}\Huge\$

$\displaystyle\frac{{\sqrt{{a}}+\sqrt{{b}}}}{\sqrt{{{a}}}}\cdot\frac{\sqrt{{{a}}}}{\sqrt{{{a}}}}=\frac{{\sqrt{{{{a}}^{{2}}}}+\sqrt{{{a}{b}}}}}{{\sqrt{{{{a}}^{{2}}}}}}=\frac{{{a}+\sqrt{{{a}{b}}}}}{{{a}}}\usepackage{cmbright}\Huge\$