Math, asked by lavya987, 9 months ago

plzz solve above 2 question
plzz do it fast plzz
and don't spam
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Answers

Answered by prince5132
16

GIVEN :-

  • (3 - √5)/(3 + 2√5) = a√5 - b

TO FIND :-

  • The value of a and b.

SOLUTION :-

→ (3 - √5)/(3 + 2√5) = a√5 - b

→[( 3 - √5)(3 - 2√5)]\[(3 + 2√5)((3 - 2√5)] = a√5- b

Using identity :- (a + b) (a - b) = a² - b².

→ [(9 - 6√5 - 3√5 + 10)/(3)² - (2√5)²] = a√5 - b

→ [( 9 + 10 - 9√5)\(9 - √25)] = a√5 - b

→ [(19 - 9√5)\(9 - 20)] = a√5 - b

→ [(19 - 9√5)/(-11)] = a√5 - b

Transfer (-) to numerator.

→ [(-19 - 9√5)/11] = a√5 - b

Arrange The L.H.S according to R.H.S.

→ (-9√5 - 19)/11 = a√5 - b

→ (-9/11)√5 - (19/11) = a√5 - b

comparing both side,

→ a = (-9/11) , b = (19/11)

Hence value of a is (-9/11) and b is (19/11)

Answered by Anonymous
59

Given :-

\rm\to\frac{3 -\sqrt{5}}{3 + 2 \sqrt{5}}  = a  \sqrt{5} - b

To Find :-

  • Value of a & b

Solution :-

\rm\frac{3 -\sqrt{5}}{3 + 2 \sqrt{5}}  = a  \sqrt{5} - b \\  \\ \implies\rm \frac{(3x -  \sqrt{5}) \: (3 - 2  \sqrt{5})}{(3 + 2 \sqrt{5}) \: (3 - 2 \sqrt{5})  }  = a \sqrt{5} - b

By using identities,

  • a² - b² = (a+ b) (a - b)

\implies\rm \frac{9 - 6 \sqrt{5} - 3 \sqrt{5} + 10  }{ {3}^{2} -  { (2\sqrt{5}) }^{2}  } = a \sqrt{5} - b \\  \\   \implies\rm \frac{9 + 10 - 9 \sqrt{5} }{9 -  \sqrt{25} } = a \sqrt{5} - b \\  \\  \implies\rm \frac{19 - 9 \sqrt{5} }{9 - 20} = a \sqrt{5} - b \\  \\  \implies\rm  \frac{ - 19 - 9 \sqrt{5} }{11} = a \sqrt{5} - b

Arrange the L.H.S according to R.H.S,

\implies\rm \frac{ - 9 \sqrt{5} - 19 }{11} = a \sqrt{5}  - b \\  \\ \implies\rm (\frac{ - 9}{11}) \:  \sqrt{5} -  \frac{19}{11} = a \sqrt{5} - b

Comparing both sides,

  • \rm a = \frac{-9}{11}, \:  b = \frac{19}{11}

\green{\bigstar \: \sf Hence, the  \: value  \: of \:  a = \frac{-9}{11}  \: and  \: b = \frac{19}{11}}

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