If a+b=11,ab=30 then find the value of a-b.
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hdewangan:
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Answers
Answered by
28
HELLO DEAR,
a+b =11-----------(1)
ab =30
==> a= 30/b --------(2)
from---(1) and----(2)
30/b + b = 11
==> (30+b²)/b = 11
==> 30 + b² = 11b
==> b² - 11b +30 =0
==> b² - 6b -5b +30 =0
==> b(b-6) - 5(b-6) =0
==> (b-5) (b-6)
b= 6
or
b =5 put in ---(2)
We get,
a×5 = 30
a = 6
if b =6
similarly,
a ×6 =30
a =5
now,
a- b = 6 - 5 = 1
or
5-6 = -1
I HOPE ITS HELP YOU DEAR,
THANKS
a+b =11-----------(1)
ab =30
==> a= 30/b --------(2)
from---(1) and----(2)
30/b + b = 11
==> (30+b²)/b = 11
==> 30 + b² = 11b
==> b² - 11b +30 =0
==> b² - 6b -5b +30 =0
==> b(b-6) - 5(b-6) =0
==> (b-5) (b-6)
b= 6
or
b =5 put in ---(2)
We get,
a×5 = 30
a = 6
if b =6
similarly,
a ×6 =30
a =5
now,
a- b = 6 - 5 = 1
or
5-6 = -1
I HOPE ITS HELP YOU DEAR,
THANKS
Answered by
21
Hi friend
---------------
Your answer
--------------------
Given that : - (a + b) = 11 and ab = 30.
To calculate : - (a - b) = ?
Now,
---–-----
(a + b) = 11
=> (a + b)² = (11)²
=> a² + 2ab + b² = 121
=> a² + b² = 121 - 2ab
=> a² + b² = 121 - (2 × 30) [ Because ab = 30.]
=> a² + b² = 121 - 60
=> a² + b² = 61
=> a² + b² - 2ab = 61 - 2ab [Subtracting 2ab from both sides .]
=> (a - b)² = 61 - (2 × 30) [Because ab = 30.]
=> (a - b)² = 61 - 60
=> (a - b)² = 1
=> (a - b) = √1
=> a - b = 1
Therefore,
------------------
a - b = 1
HOPE IT HELPS
---------------
Your answer
--------------------
Given that : - (a + b) = 11 and ab = 30.
To calculate : - (a - b) = ?
Now,
---–-----
(a + b) = 11
=> (a + b)² = (11)²
=> a² + 2ab + b² = 121
=> a² + b² = 121 - 2ab
=> a² + b² = 121 - (2 × 30) [ Because ab = 30.]
=> a² + b² = 121 - 60
=> a² + b² = 61
=> a² + b² - 2ab = 61 - 2ab [Subtracting 2ab from both sides .]
=> (a - b)² = 61 - (2 × 30) [Because ab = 30.]
=> (a - b)² = 61 - 60
=> (a - b)² = 1
=> (a - b) = √1
=> a - b = 1
Therefore,
------------------
a - b = 1
HOPE IT HELPS
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