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
12
15
18
Answer: Option
Explanation:

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

   = 29 - 9 = 20

   ab = 10.

Discussion:
107 comments Page 7 of 11.

Tanim Ehsan said:   9 years ago
If a + b = 13 and ab = 3 then (a+2b)^2-5b^2 = ?

Simplify the solution.

Sonali said:   9 years ago
a-b = 3, a2+b2=29, ab =?
(a-b)2 = a2+b2-2ab
2ab = (a2+b2)-(a-b)2
ab = 29-9/2
= 20/2 = 10 Ans.

Gyanika said:   9 years ago
Can somebody please solve this question.

a - b = 1, 2a + 20 = b. Then a, b is?

Francium said:   9 years ago
Guys, please solve this for me a2 + b2 = 36 and an=7 find the value of (a+b)2.

Rah1 said:   9 years ago
Awesome answer @Ram.

Anil malav said:   9 years ago
(a^2 + b^2)^1/2 = 613 then find the value of a+b.

Solve and find the answer.

Neeraj Kashyap said:   9 years ago
Please solve the following with explanation:

1. (a + b) (a - b) + (2a + b) (2a - 3b).
2. (x - y)(2x + y) - (x + y)(2x - y).
3. (x + 6){5x - 3(x - 2)}
4. 7x - 3{x - 2x(x - 4)}

Nagaraj said:   9 years ago
a^2+b^2 = 29,
a = 5, b = 2.
5^2 + 2^2 = 29.

Thank you.

John audu said:   9 years ago
@Gh Mustafa

If a ^2+b^2=16 and (a - b)^2 = 4 = (a2 + b2) = 16 (a2 - b2) = 4.

Clear thé bracket = a + b = 16, a - b = 4.
Since we are finding ab = a + b = 16/4 = 4. So, a + b = ab.ab = 4.

GH MUSTAFA said:   9 years ago
How can solve this a^2 + b^2 = 16 and (a - b)^2 = 4 then ab is equal to?


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