If x^2 + 9/x^2 = 10, what is the value of x - 3/x	Choose the correct option.
A) 36	B) 25	C) 2	D) 5	E) 3

Rationale: to find : x - 3 / x . let it be t . = > x - 3 / x = t = > ( x ^ 2 + 9 / x ^ 2 ) - 2 * x * 3 / x = t ^ 2 ( squaring both sides ) . = > ( 10 ) - 2 * 3 = 4 = > t ^ 2 = 4 . thus t = 2 or t = - 2 . answer c
Answer: C