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If 1/x + 1/y = 3 and 1/x - 1/y = 7, what is the value of x + y? Express your answer as a common fraction.

 Jun 24, 2022
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1/x  + 1/y =  3

1/x  -  1/y  = 7          add these

 

2 / x =  10

 

x = 2/10  = 1/5

 

 

And  

 

1 / (1/5) + 1/y = 3

 

5 + 1/y=  3

 

1/y =  3 -5

 

1/y =  -2

 

y  = -1/2

 

x + y =   1/5  - 1/ 2 =   -3 /  10

 

 

 

 

cool cool cool

 Jun 24, 2022
edited by CPhill  Jun 24, 2022

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