Choose the one alternative that best completes the statement or answers the question.
Multiply. Assume all variables represent nonnegative real numbers.
-$\sqrt { 7 } ( \sqrt { 343 } - \sqrt { 7 } )$
A) 56
B) 42
C) $49 - \sqrt { 7 }$
D) $7 \sqrt { 7 } - 7$

Question

Quizplus · Accepted Answer

First, simplify $\sqrt{343}$ to $7\sqrt{7}$ because $343 = 7^3$, and then distribute $\sqrt{7}$ across the terms inside the parentheses. This gives $\sqrt{7} \cdot 7\sqrt{7} - \sqrt{7} \cdot \sqrt{7} = 7 \cdot 7 - 7 = 49 - 7 = 42$.

Choose the One Alternative That Best Completes the Statement or Answers