Aptitude - Surds and Indices - Discussion

Discussion Forum : Surds and Indices - General Questions (Q.No. 15)
15.
If x = 3 + 22, then the value of x - 1 is:
x
1
2
22
33
Answer: Option
Explanation:

x - 1 2 = x + 1 - 2
x x

   = (3 + 22) + 1 - 2
(3 + 22)

   = (3 + 22) + 1 x (3 - 22) - 2
(3 + 22) (3 - 22)

   = (3 + 22) + (3 - 22) - 2

   = 4.

x - 1 = 2.
x

Discussion:
48 comments Page 5 of 5.

Sefah said:   1 decade ago
How do we get the square in the 1st step because it wasn't part of the question?

Gayathri said:   1 decade ago
Here given 'x' value only not root 'x'. So answer is 2(1+root2).

Nicky said:   10 years ago
Why we subtract -2 in 1st step?

Srinivas said:   10 years ago
4th step is the problem. Where did the denominator go. No proper explanation.

Ahmed said:   9 years ago
Actual answer is 4, but why should be 2.

Suma said:   9 years ago
Answer is 4 how do you get 2?

Vijay said:   9 years ago
Please explain how they take ^2over it?

Priyanka said:   9 years ago
Why -2 is wriiten at the end ? From where it came ?


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