# 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 4*a*^{2} - 4*a* + 1 + 3*a* is:

Answer: Option

Explanation:

4*a*^{2} - 4*a* + 1 + 3*a*
= (1)^{2} + (2*a*)^{2} - 2 x 1 x 2*a* + 3*a*

= (1 - 2*a*)^{2} + 3*a*

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

= (1 + *a*)

= (1 + 0.1039)

= 1.1039

Discussion:

70 comments Page 1 of 7.
Pallavi said:
1 year ago

Any anyone explain this clearly.

Uyog said:
2 years ago

Guys..this will make you understand,

Its 4a^2 * 4a+1... i.e a * 2ab+b^2.where a=2a...(4a^2) and b=1...

So, we got formula of (a-b)^2..removing root..i.e (a-b).

We get,

(2a-1)+3.

(2 * 0.1039- 1) + 3(0.1039).

(0.2078-1) + 0.3117.

0.7922 + 0.31 17.

1.1039.

Its 4a^2 * 4a+1... i.e a * 2ab+b^2.where a=2a...(4a^2) and b=1...

So, we got formula of (a-b)^2..removing root..i.e (a-b).

We get,

(2a-1)+3.

(2 * 0.1039- 1) + 3(0.1039).

(0.2078-1) + 0.3117.

0.7922 + 0.31 17.

1.1039.

(1)

Mukesh Chauhan said:
2 years ago

Two answers are possible here.

One is: 2a-1 and 1-2a because the square of both numbers are the same.

Anyone, please clear this.

One is: 2a-1 and 1-2a because the square of both numbers are the same.

Anyone, please clear this.

Siri said:
3 years ago

I am not understanding this whole solution, can someone explain to me in an easy manner?

Khushi said:
3 years ago

Why w (1-2a) ^2, whekat ey not (2a-1) ^2?

Please tell me.

Please tell me.

Chinnapa reddy said:
3 years ago

I have one doubt about the solution to the problem why should we take 1-2*a only, there is another chance to take equation as 2*a-1 please tell me a solution.

Dinesh Choudhury said:
4 years ago

2a<1 so use (1-2a)^2.

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

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

Varsha jadhav said:
5 years ago

@All.

We can take positive or negative square root that is (2a-1) or -(2a-1) => (1-2a) but according to the given option we need a positive value if we consider the value (2a-1) then the answer will be negative.

=> (2a-1)+3a.

=> 5a-1,

=>5*0.1039-1,

=>0.5195-1,

=>-0.4855.

but if we put the value (1-2a) then the calculation will be;

=>(1-2a)+3a.

=>1+a,

=>1+0.1039,

=>1.1039.

We can take positive or negative square root that is (2a-1) or -(2a-1) => (1-2a) but according to the given option we need a positive value if we consider the value (2a-1) then the answer will be negative.

=> (2a-1)+3a.

=> 5a-1,

=>5*0.1039-1,

=>0.5195-1,

=>-0.4855.

but if we put the value (1-2a) then the calculation will be;

=>(1-2a)+3a.

=>1+a,

=>1+0.1039,

=>1.1039.

Surya said:
5 years ago

Why not 2a-1?

How can 1-2a?

How can 1-2a?

Sintu Kumar said:
5 years ago

@Krishna.

But, my factor is (2a-1)(2a-1).

Than 2a-1+3a,

=5a-1,

=5*0.1039-1.

=0.5195-1=-0.4805.

But, my factor is (2a-1)(2a-1).

Than 2a-1+3a,

=5a-1,

=5*0.1039-1.

=0.5195-1=-0.4805.

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