Question
Question: If [x<sup>2</sup>] + x − a = 0 has a solution where a ∈ N and a ≤ 20, then total number of different...
If [x2] + x − a = 0 has a solution where a ∈ N and a ≤ 20, then total number of different values of 'a' can be
A
2
B
3
C
4
D
6
Answer
4
Explanation
Solution
[x2] + x − a = 0 ⇒ 'x' has to be an integer.
⇒ a = x2 + x = x(x + 1).
Thus 'a' can be 2, 6, 12, 20