Evaluate 9 square root of 7- square root of 28

$9 \sqrt{7} - \sqrt{28}$

Step 1

Simplify each term.

Rewrite $28$ as $2^{2} \cdot 7$ .

Factor $4$ out of $28$ .

$9 \sqrt{7} - \sqrt{4 (7)}$

Rewrite $4$ as $2^{2}$ .

$9 \sqrt{7} - \sqrt{2^{2} \cdot 7}$

$9 \sqrt{7} - \sqrt{2^{2} \cdot 7}$

Pull terms out from under the radical.

$9 \sqrt{7} - (2 \sqrt{7})$

Multiply $2$ by $- 1$ .

$9 \sqrt{7} - 2 \sqrt{7}$

$9 \sqrt{7} - 2 \sqrt{7}$

Step 2

Subtract $2 \sqrt{7}$ from $9 \sqrt{7}$ .

$7 \sqrt{7}$

Step 3

The result can be shown in multiple forms.

Exact Form:

$7 \sqrt{7}$

Decimal Form:

$18.52025917 \dots$

Related Questions