An easy one

Algebra Level 2

If 2 x + 3 y = 2 , 4 x − 9 y = − 1 \frac { 2 }{ \sqrt { x } } +\frac { 3 }{ \sqrt { y } } =2,\frac { 4 }{ \sqrt { x } } -\frac { 9 }{ \sqrt { y } } =-1 find x + y x+y where x , y x,y are positive integers.


The answer is 13.

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Shivamani Patil by shivamani patil , 21, India

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2 solutions

Use the method of elimination. Let the first equation be (1) and the second one be (2). (2)- 2x(1) gives -15/√y= -5, giving y=9. Substituting y=9 in equation (1) gives x=4. Thus, x+y = 4+9 =13

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That's what I did.

Sam Maltia - 5 years, 8 months ago
Aditya Chauhan
Apr 18, 2015

Just substitute 1/√x as some variable 'a' and 1/√y as 'b' On solving u will get a=1/2 and b=1/3 Then put 'a' as 1/√x and 'b' as 1/√y And then u will get x=4 and y=9

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