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10/x+y +2/x-y , 15/x+y - 5/x-y …

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10/x+y +2/x-y , 15/x+y - 5/x-y solve the pair of equation by them to a pair of linear equation
  • 1 answers

Gaurav Seth 5 years, 3 months ago

Given equations are ,

 

10/( x + y ) + 2/( x - y ) = 4 ---( 1 )

 

15/( x + y ) - 5/( x - y ) = -2 --( 2 )

 

Let ,

 

1/(x+y) = a , 1/(x-y) = b

 

10a + 2b = 4

 

Divide each term with 2 , we get

 

5a + b = 2

 

=> b = 2 - 5a ----( 3 )

 

15a - 5b = -2 -----( 4 )

 

Substitute b = 2 - 5a in equation

 

( 4 ) , we get

 

15a - 5( 2 - 5a ) = -2

 

=> 15a - 10 + 25a = -2

 

=> 40a = -2 + 10

 

=> 40a = 8

 

=> a = 8/40

 

=> a = 1/5

 

Put a = 1/5 in equation ( 3 ) , we

 

get

 

b = 2 - 5 × 1/5

 

=> b = 2 - 1

 

b = 1

 

Therefore ,

 

1/( x + y ) = 1/5 => x + y = 5 --( 5 )

 

1/(x-y) = 1/1 => x - y = 1 ---( 6 )

 

Add equations ( 5 ) and ( 6 ) ,

 

We get

 

2x = 6

 

=> x = 6/2 = 3 ,

 

Put x = 3 in equation ( 5 ) , we get

 

3 + y = 5


 

=> y = 5 - 3 = 2

 

Therefore ,

 

x = 3 , y = 2

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