Aptitude - Square Root and Cube Root - Discussion

Discussion Forum : Square Root and Cube Root - General Questions (Q.No. 6)
6.

If a = 0.1039, then the value of 4a2 - 4a + 1 + 3a is:

0.1039
0.2078
1.1039
2.1039
Answer: Option
Explanation:

4a2 - 4a + 1 + 3a = (1)2 + (2a)2 - 2 x 1 x 2a + 3a

   = (1 - 2a)2 + 3a

   = (1 - 2a) + 3a

   = (1 + a)

   = (1 + 0.1039)

   = 1.1039

Discussion:
71 comments Page 6 of 8.

Maurya said:   8 years ago
Since all the options are positive we have to choose (1-2a).

Sandeep said:   9 years ago
@DIVI.
Answer will be in -ve if you subtracting 0.5195 - 1.

Khushi said:   5 years ago
Why w (1-2a) ^2, whekat ey not (2a-1) ^2?

Please tell me.
(3)

Tanvi said:   1 decade ago
Yes, Mariapan,
I agree with you.
Why it's not (2a-1)?

Rahul said:   9 years ago
I do not understand the explanation. Please clarify me.

Gopal said:   7 months ago
Yes, @Varsha Jadhav.

The actual answer is -0.4805.
(2)

Mannoj kumar said:   1 decade ago
I agree with sayani. We need to see the options also.

Sarath said:   1 decade ago
But I get (a-1/2) using (-b + -sqrt (b2 - 4ac) /2a).

Sam said:   1 decade ago
Anoop's ans shd be the right one....Thanks Anoop..

Shivam said:   1 decade ago
Not getting how can we take decision at exam time.


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