plzzzz give me the ans of this question
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- a²+4b²=41
- ab=10
- now, (a+2b)²=a²+4b²+4ab
- =41+40=81
- so,a+2b=9
- and,(a-2b)²=a²+4b²-4ab
- so,a-2b= 1
aanya2588:
thats not 9+ its If
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Given
a^2 + 4b^2 = 41
ab = 10
we know that
(a + b)^2 = a^2 + b^2 +2ab
here a = a , b= 2b
so..
(a + 2b)^2
= a^2 + (2b)^2 + 2(a)(2b)
=a^2 + 4b^2 + 4ab
substitute given values...
= 41 + 4(10) = 81
(a+ 2b)^2 = 81
(a + 2b) = √81 = 9.....
Similarly We know that...
(a-b)^2 = a^2 +b^2 - 2ab or ( a+b)^2 - 4ab
here a = a , b = 2b
(a - 2b)^2 = (a^2 + (2b)^2 -2.a.2b) = a^2 + 4b^2 - 4ab
substitute given values...
= 41 - 4(10)
= 41 - 40
= 1
so (a-2b)^2 = 1..
(a-2b) = √1 = 1....
so
a + 2b = 9
a - 2b = 1........
a^2 + 4b^2 = 41
ab = 10
we know that
(a + b)^2 = a^2 + b^2 +2ab
here a = a , b= 2b
so..
(a + 2b)^2
= a^2 + (2b)^2 + 2(a)(2b)
=a^2 + 4b^2 + 4ab
substitute given values...
= 41 + 4(10) = 81
(a+ 2b)^2 = 81
(a + 2b) = √81 = 9.....
Similarly We know that...
(a-b)^2 = a^2 +b^2 - 2ab or ( a+b)^2 - 4ab
here a = a , b = 2b
(a - 2b)^2 = (a^2 + (2b)^2 -2.a.2b) = a^2 + 4b^2 - 4ab
substitute given values...
= 41 - 4(10)
= 41 - 40
= 1
so (a-2b)^2 = 1..
(a-2b) = √1 = 1....
so
a + 2b = 9
a - 2b = 1........
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