If 30x2 - 15x + 1 = 0, then what is the value of 25x2 + (36x2)-1?
Show answer & explanation
Correct answer: B
Explanation
The correct answer is Option 2 i.e 
Given,
30x2 - 15x + 1 = 0 ---------------------------- eqn 1
We need to find the value of (5x)2 + (1/6x)2. For this,
Dividing equation 1 by 6x, we get;
5x + (1/6x) = 5/2
Now,
(5x)2 + (1/6x)2 = (5/2)2 - 2 × 5 × 1/6
= (25/4) - (5/3)
= 55/12