- A(5 + √21)/2
- B(5 − √21)/2
- C5 + √21
- D(10 + 2√21)/10
Step-by-Step Solution
Multiply above and below by the conjugate √7 + √3. The numerator becomes √21 + 3 = 10 + 2√21, and the denominator becomes 7 − 3 = 4. So the value is (10 + 2√21)/4 = (5 + √21)/2 ≈ 4.79, which matches 4.378 ÷ 0.914.
Answer: A) (5 + √21)/2