Answer
70
Work Step by Step
First of all, in order to make this one large square root, we multiply the coefficients to obtain that the new coefficient is 10. Also, recall, $\sqrt{a}\times \sqrt{b}= \sqrt{a \times b}$. Thus, we can multiply 7 and 7 to obtain the simplified expression:
$10\sqrt{7 \times 7}=10\sqrt{7^{2}}=70$
