Evaluate square root of 87- square root of 36

$\sqrt{87 - \sqrt{36}}$

Step 1

Rewrite $36$ as $6^{2}$ .

$\sqrt{87 - \sqrt{6^{2}}}$

Step 2

Multiply.

Pull terms out from under the radical, assuming positive real numbers.

$\sqrt{87 - 1 \cdot 6}$

Multiply $- 1$ by $6$ .

$\sqrt{87 - 6}$

Step 3

Subtract $6$ from $87$ .

$\sqrt{81}$

Step 4

Rewrite $81$ as $9^{2}$ .

$\sqrt{9^{2}}$

Step 5

Pull terms out from under the radical, assuming positive real numbers.

$9$