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.
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.
Yaswanth chinni said:
9 years ago
2ab = (a2 + b2) - (a - b)2.
= 29 - 9 = 20,
ab = 10.
= 29 - 9 = 20,
ab = 10.
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.
Mangesh said:
9 years ago
Please give the answer of (a-b) =4 ab=52.25 then a^2 * b^2 = ?
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.
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.
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?
Sachin Kumar said:
8 years ago
If a^2+b^2 = (a+b)^2.
And (a+b)^2 = a^2+b^2+2ab.
It means a^2+b^2 = a^2+b^2+2ab.
But How Could it Possible,
Please somebody tell me what actually is it?
And (a+b)^2 = a^2+b^2+2ab.
It means a^2+b^2 = a^2+b^2+2ab.
But How Could it Possible,
Please somebody tell me what actually is it?
Sachin Kumar said:
8 years ago
@Gween.
a + b = 4
means a=4-b.
Put this value in the equation
5= 2(4-b)+3b,
5= 8-2b+3b,
5-8 = -2b+3b,
-3= b.
Put the value of b in the equation and u will get the value of a.
Thats it!
a + b = 4
means a=4-b.
Put this value in the equation
5= 2(4-b)+3b,
5= 8-2b+3b,
5-8 = -2b+3b,
-3= b.
Put the value of b in the equation and u will get the value of a.
Thats it!
Sourav Das said:
8 years ago
If a+b = √5 & a-b= √3 than find the value of a2 + b2.
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