Problem 9 · 2016 Math Kangaroo
Medium
Algebra & Patterns
substitution
If \(x^2 - 4x + 2 = 0\), then \(x + \dfrac{2}{x}\) equals
Show answer
Answer: E — 4
Show hints
Hint 1 of 2
You never need the actual value of \(x\); reshape the equation toward \(x + \tfrac{2}{x}\).
Still stuck? Show hint 2 →
Hint 2 of 2
Divide the whole equation by \(x\).
Show solution
Approach: divide through by x
- From \(x^2 - 4x + 2 = 0\), regroup as \(x^2 + 2 = 4x\).
- Divide both sides by \(x\): \(x + \dfrac{2}{x} = 4\).
- So the value is 4 (E).
Mark:
· log in to save