Question

Simplify the sum or difference: $3\sqrt{7}-\sqrt{63}$

• A. $-2\sqrt{7}$
• B. $-6\sqrt{7}$
• C. $-4\sqrt{3}$
• D. $0$

Answer 1

The correct option is D

$0$

Explanation for the correct option:

Given that $3\sqrt{7}-\sqrt{63}$

By subtracting we get,
$$\begin{gathered} 3\sqrt{7}-\sqrt{63}=3\sqrt{7}-\sqrt{9\times 7} \\ =3\sqrt{7}-3\sqrt{7} \\ =0 \end{gathered}$$

Hence, option(D) is correct.