passwella.
Menu

JAMB Mathematics 1999 Question 4

Question 4

Surds

Find the value of x if √2/(x + √2) = 1/(x − √2)

  1. A.3√2 + 4
  2. B.3√2 − 4
  3. C.3 − 2√2
  4. D.4 + 2√2
Show the answer and explanation

Answer: A (3√2 + 4)

Explanation

Cross-multiply: √2x − 2 = x + √2, so x(√2 − 1) = 2 + √2. Multiply top and bottom by √2 + 1: x = (2 + √2)(√2 + 1) = 4 + 3√2.