The sum of a number and its reciprocal is 3415. Find the number.
Answer:
35 or 53
- Let the number is x. Then
x+1x=3415⟹x2+1x=3415⟹15x2+15=34x⟹15x2−34x+15=0⟹15x2−9x−25x+15=0⟹3x(5x−3)−5(5x−3)=0⟹(3x−5)(5x−3)=0 - Hence, x=35 or 53