Aptitude - Simplification - Discussion

Discussion Forum : Simplification - General Questions (Q.No. 4)
4.
If a - b = 3 and a2 + b2 = 29, find the value of ab.
10
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Answer: Option
Explanation:

2ab = (a2 + b2) - (a - b)2

   = 29 - 9 = 20

   ab = 10.

Discussion:
107 comments Page 3 of 11.

Bhavana said:   1 decade ago
I didn't get the fifth line. Can you explain it.

Krishna said:   1 decade ago
a^2+b^2=(a-b)(a-b)+2ab. Now putting the value of (a-b)we get that 9+2ab=29, 2ab=20, ab=10.

Krishna said:   1 decade ago
a2+b2=(a-b)(a-b)+2ab hota hi 3*3+2ab=29,2ab=20,ab=10

Suganya said:   1 decade ago
Sathish said correct solution and take a time shortly to solve the problem.

Ram said:   1 decade ago
(a+b)^2-(a-b)^2 = 4ab.

Arshiya said:   1 decade ago
If (a-b) = 7 ab = 9, then find the value of (a2+b2)?

Prasad said:   1 decade ago
(a-b)^2 = a^2+b^2-2ab.

Then 2ab = (a^2+b^2)-(a-b)^2.

2ab = 29-(3)^2.
2ab = 20.

ab = 10.

Manjunatha dv said:   1 decade ago
a-b = 3.
5-2 = 3.

a^2+b^2 = 29.
5^2+2^2 = 29.

Answer = 5*2 = 29.

Harisha said:   10 years ago
Solve the problem if a+1/a-2=4. Find the value of (a-2)^2+(1/a-2)^2?

Jisha said:   10 years ago
@Harisha can you explain your question?


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