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deleted.

 Jun 10, 2019
edited by sinclairdragon428  Jun 10, 2019
edited by sinclairdragon428  Jun 10, 2019
edited by sinclairdragon428  Nov 20, 2019
 #1
avatar+396 
0

Positive integers x and y have a product of 56 and x

 Jun 10, 2019
 #2
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+1

x * y = 56..............................(1)

7*1/x  +  14*1/y = 4...................(2)

Can you solve the 2 simultaneous equations? Try it.

 Jun 10, 2019
edited by Guest  Jun 10, 2019
 #3
avatar+111400 
+1

xy = 56   ⇒  y = 56/x

 

And

 

7 (1/x) +  14(1/y) = 4

 

7/x + 14/y  = 4

 

7/x + 14 / (56/x)  = 4

 

7/x + (14/56)x  = 4

 

7/x + (1/4) x  = 4          multiply through by  4x

 

28 + x^2 = 16x           rearrange as

 

x^2 - 16x + 28  = 0      factor as

 

(x - 14) ( x - 2)  = 0

 

Set each factor to 0  and solve for x   and we have that

 

x = 14     or x = 2 

 

And y =

 

56/14 = 4     or   56/2 = 28

 

So  (x,y)   = (2, 28)

 

 

cool cool cool

 Jun 10, 2019
 #4
avatar+396 
-1

Thanks!

sinclairdragon428  Jun 10, 2019

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