Solve -sqrt{81/2}

$$- \sqrt{ \frac{ 81 }{ 2 } }$$

Evaluate

$$-\frac{9\sqrt{2}}{2}\approx -6.363961031$$

Solution Steps

Rewrite the square root of the division \sqrt{\frac{81}{2}} as the division of square roots \frac{\sqrt{81}}{\sqrt{2}}.

$$-\frac{\sqrt{81}}{\sqrt{2}}$$

Calculate the square root of 81 and get 9.

$$-\frac{9}{\sqrt{2}}$$

Rationalize the denominator of \frac{9}{\sqrt{2}} by multiplying numerator and denominator by \sqrt{2}.

$$-\frac{9\sqrt{2}}{\left(\sqrt{2}\right)^{2}}$$

The square of \sqrt{2} is 2.

$$-\frac{9\sqrt{2}}{2}$$