x , y , z are non-zero real numbers such that:
x+y=4xy
y+z=6yz
z+x=8zx
If x + y + z = b a where a , b are positive coprime integers, what is a + b ?
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I also did the exact same way!
same here!!@@!!
quite beautiful and elegant solution!!!!!!!!!!!!!!!
Done the same way :)
@Divyansh Singhal and @Jai gupta The answer could also be x = y = z = 0
Otherwise, elegant solution.
I solved for y in terms of x in the first equation: y = 4 x − 1 x . Then I solved for z in terms of y in the second equation: z = 6 y − 1 y . Substituting the first equation into the second gives the complex fraction: z = 4 x − 1 6 x − 1 4 x − 1 x . After simplifying, I got z = 2 x + 1 x . Next, I substituted 2 x + 1 x in for z in the third equation: 2 x + 1 x + x = 8 2 x + 1 x x ⇒ x + 2 x 2 + x = 8 x 2 ⇒ 2 x = 6 x 2 ⇒ x = 3 1 . Finally, substituting x = 3 1 in y = 4 x − 1 x and z = 2 x + 1 x , I get the final answer
( x , y , z ) = ( 3 1 , 1 , 5 1 ) .
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Let x+y=4xy ..........(1) y+z=6yz ...........(2) z+x=8zx .............(3) Divide (1) by xy, Divide (2) by yz, Divide (3) by zx. Then you will get three equations
1.(1/x)+(1/y)=4
2.(1/y)+(1/z)=6
3.(1/z)+(1/y)=8
Three equation three variable and you will get x=1/3,y=1,z=1/5 x+y+z=23/15
Hence the answer is 23+15=38