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.
Answer: Option
Explanation:
2ab = (a2 + b2) - (a - b)2
= 29 - 9 = 20
ab = 10.
Discussion:
107 comments Page 4 of 11.
SMRUTI RANJAN said:
9 years ago
If a2 - b2 = 37, then a2 + b2 = ? Please explain?
Saad said:
9 years ago
If a2 - b2 = 30 and a - b = 5, then find the value of ab?
Hepinder happy said:
9 years ago
@Saad.
a^2 - b^2 = (a+b)(a-b) we have given a^2 - b^2 = 30 and a - b= 5.
Then (a + b)(a - b) = 30.
a + b = 30/(a -b).
a + b = 30/5.
a + b = 6
Solving 1 & 2 we get,
2a = 11.
a = 11/2 then ab =11/4 --> Answer.
a^2 - b^2 = (a+b)(a-b) we have given a^2 - b^2 = 30 and a - b= 5.
Then (a + b)(a - b) = 30.
a + b = 30/(a -b).
a + b = 30/5.
a + b = 6
Solving 1 & 2 we get,
2a = 11.
a = 11/2 then ab =11/4 --> Answer.
Amit said:
9 years ago
It's so easy Easy method.
Given.
a - b = 3 and a * a - b * b = 3,
So,
a = 5 and b = 2.
Then,
ab = 5 * 2 = 10.
Given.
a - b = 3 and a * a - b * b = 3,
So,
a = 5 and b = 2.
Then,
ab = 5 * 2 = 10.
Antara chatterjee said:
9 years ago
a2 + b 2= 52,and a - b = 2. Then ab?
Anyone solve this problem.
Anyone solve this problem.
Rushah said:
9 years ago
@Antara.
It's very easy. Remove brackets and multiply you got 2ab.
It's very easy. Remove brackets and multiply you got 2ab.
Raj said:
9 years ago
If a + 1/a = 4, then a^2 + 1/a^2 = ?
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?
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.
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.
Nagaraj said:
9 years ago
a^2+b^2 = 29,
a = 5, b = 2.
5^2 + 2^2 = 29.
Thank you.
a = 5, b = 2.
5^2 + 2^2 = 29.
Thank you.
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