Multiply, and then simplify if possible. Assume all variables represent positive real numbers.
-$\sqrt { 7 } ( \sqrt { 63 } + \sqrt { 21 } )$
A) 42
B) $441 + 7 \sqrt { 3 }$
C) $21 + 7 \sqrt { 3 }$
D) $21 + 49 \sqrt { 3 }$

Question

Quizplus · Accepted Answer

First, distribute $\sqrt{7}$ to both terms inside the parentheses: $\sqrt{7} \cdot \sqrt{63} + \sqrt{7} \cdot \sqrt{21}$. This simplifies to $\sqrt{441} + \sqrt{147}$, which further simplifies to $21 + 7\sqrt{3}$.

Multiply, and Then Simplify If Possible 7(63+21)\sqrt { 7 } ( \sqrt { 63 } + \sqrt { 21 } )7​(63​+21​)

Multiply, and Then Simplify If Possible $\sqrt { 7 } ( \sqrt { 63 } + \sqrt { 21 } )$