Simplify \(\frac{20}{5\sqrt{28} - 2 \sqrt{63}}\)
A
\(\frac{5\sqrt{7}}{7}\)
B
\(\frac{5\sqrt{5}}{7}\)
C
\(\frac{7\sqrt{5}}{7}\)
D
\(\frac{7\sqrt{7}}{5}\)
Verified Correct Answer: A.
Step-by-Step Mathematical Solution
\(\frac{20}{5 \sqrt{4 \times 7} - 2\sqrt{9 \times 7}}\)
\(\frac{20}{10 \sqrt{7} - 6\sqrt{7}}\)
= \(\frac{20 \sqrt{7}}{4 \sqrt{7}}\)
= \(\frac{5\sqrt{7}}{7}\)
Source: Myschool Past Questions Archive (Record #36200)