Question

If a+b=11,ab=30 then find the value of a-b.

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Answer 1

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

Answer 2

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