Question

linear equations in two variable.
Solve for x and y,...
(ques in pic.)

Answer 1

Let

1/(x+y) = a 

1/(x-y) = b
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  5a -  2b =  -1         --------1equation 
15a + 7b =  10        -----2equation 
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5a - 2b = -1      multiply by 7
15a + 7b = 10    multiply by 2
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35a - 14b  =  -7
30a + 14b =  20
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65a = 13 

a =13/65

a=  1/5

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putting the value of a in 1equation 

5a -2b = -1

5(1/5)  - 2b = -1

1 - 2b = -1 

- 2b =  -1-1 

-2b = -2

2b = 2

b = 2/2 

b =1 
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a =x+y = 1/5     -----3equation

b = x-y = 1     --------4equation 

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add 3& 4 equation 

x+y = 1/5
x-y = 1

2x = 1/5 + 1 

2x =(1+5)/5

2x =6/5

x =6/10 = 3/5
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putting the value of x in 3equation,

3/5 + y = 1/5 

y = 1/5 - 3/5

y =(1-3)/5

y =  -2/5
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x = 3/5

And

y=  -2/5

i hope this will help you

-by ABHAY