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 5 of 8.

Bujji said:   1 decade ago
How we get the formula. I can't understand, give me the clarification about it.

Phani said:   10 years ago
Why should we take (1-2a) and the given is 4a^2 -4a+1 we can also take 2a-1.

Abhilash said:   1 decade ago
According to the solution we have to follow! that is called reasoning!

Mitz said:   1 decade ago
In this case ans. Can also proceed with (2a - 1)^2 ??? Plz clarify !!

Sujith said:   1 decade ago
We can use both (2a-1), (1-2a). Its just based on options they given.

Prince said:   1 decade ago
Please explain me these step

=(1 - 2a)^2 + 3a

= (1 - 2a) + 3a

Sundar said:   1 decade ago
Formula: a2 + b2 - 2ab = (a - b)2

Rahul said:   1 decade ago
+*- = -

Then how it bcmz (1-2a)+3a = 1+a ?

Anyone can tell?

Dinesh Choudhury said:   6 years ago
2a<1 so use (1-2a)^2.

But (2a-1)^2 is a imaginary number.
(4)

Kavitha said:   1 decade ago
Please clarify why you are using (1-2a)^2. Why not (2a-1)^2.


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