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 5 of 11.
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.
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.
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?
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.
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