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 6 of 11.
Gween said:
8 years ago
Please give me the answer of this? I don't get it.
What are the values of a and b in the equation 2a+3b = 5 if the sum of a and b is 4?
What are the values of a and b in the equation 2a+3b = 5 if the sum of a and b is 4?
Pramod kumar said:
8 years ago
Simple solution:
a - b = 3 ---> (1);
a^2+b^2 = 29 ---> (2);
Then we add 2ab and subtract 2ab in equation 2;
a^2+b^2 - 2ab+2ab = 29;
Then we get,
(a - b)^2+2ab = 29.
2ab = 29 - (a - b)^2.
Then we put value of a - b=3;
2ab=29 - 9;
2ab = 20;
ab = 10.
a - b = 3 ---> (1);
a^2+b^2 = 29 ---> (2);
Then we add 2ab and subtract 2ab in equation 2;
a^2+b^2 - 2ab+2ab = 29;
Then we get,
(a - b)^2+2ab = 29.
2ab = 29 - (a - b)^2.
Then we put value of a - b=3;
2ab=29 - 9;
2ab = 20;
ab = 10.
Rowwah said:
8 years ago
(a-b)^2 = a^2 + b^2 - 2ab,
(3)^2 = 29 - 2ab,
2ab = 29 - 9 = 20
ab = 10.
(3)^2 = 29 - 2ab,
2ab = 29 - 9 = 20
ab = 10.
Mangesh said:
9 years ago
Please give the answer of (a-b) =4 ab=52.25 then a^2 * b^2 = ?
Sandilya said:
9 years ago
Yes @Harsh Singh.
(a+b)2 = (a-b)2+4ab,
(a+b)2 = 256,
a+b = +-16.
+-16 is the answer.
(a+b)2 = (a-b)2+4ab,
(a+b)2 = 256,
a+b = +-16.
+-16 is the answer.
Yaswanth chinni said:
9 years ago
2ab = (a2 + b2) - (a - b)2.
= 29 - 9 = 20,
ab = 10.
= 29 - 9 = 20,
ab = 10.
Venkat@rockzzzz said:
9 years ago
(a-b)^2 = a^2+b^2-2ab.
2ab = a^2+b^2-(a-b)^2,
= 29-3^2,
= 29-9,
2ab = 20.
ab =10.
2ab = a^2+b^2-(a-b)^2,
= 29-3^2,
= 29-9,
2ab = 20.
ab =10.
Venkat@rockzzzz said:
9 years ago
(a-b)^2 = a^2+b^2-2ab.
2ab = a^2+b^2-(a-b)^2,
= 29-3^2,
= 29-9,
2ab = 20.
ab =10.
2ab = a^2+b^2-(a-b)^2,
= 29-3^2,
= 29-9,
2ab = 20.
ab =10.
Harsh singh said:
9 years ago
Yes @Bonjor.
(a+b)2 = (a-b)2+4ab,
(a+b)2 = 256,
a+b = +-16.
+-16 is the answer.
(a+b)2 = (a-b)2+4ab,
(a+b)2 = 256,
a+b = +-16.
+-16 is the answer.
Bonjor said:
9 years ago
I would be grateful if anyone answers this question.
If a-b=4 and ab=60 then find the value of a+b.
I found that the answer is + or - 16 what is + or -? Please tell me.
If a-b=4 and ab=60 then find the value of a+b.
I found that the answer is + or - 16 what is + or -? Please tell me.
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