Problem
When \( x=2 \), which expression can be completely simplified to \( 4 \sqrt{5} \) ? A. \( 2 \sqrt{5 x} \) B. \( 2 \sqrt{10 x} \) C. \( 5 \sqrt{2 x} \) D. \( 8 \sqrt{5 x} \)
Solution
Step 1 ：Substitute \( x=2 \) into each expression
Step 2 ：A: \( 2 \sqrt{5 \cdot 2} = 2 \sqrt{10} \)
Step 3 ：B: \( 2 \sqrt{10 \cdot 2} = 2 \sqrt{20} = 4 \sqrt{5} \)
