



 
Hi Gaby. You are certainly using the right approach, so I think you must have made an error in your arithmetic somewhere. When I substitute (9x) in place of y in the equation x^{2 }+ y^{2} = 41, I get a simple quadratic that you can easily factor and get two values of x. Then you can use each of those values to determine two corresponding values of y. I get nice whole numbers and no negative under the radical, so just check your arithmetic. Stephen La Rocque.> Hello Gaby, You first need to translate the question,look at this similar problem; the sum of two numbers is 7. the sum of the squares of the two nummbers is 25. find the two numbers.
If we solve the first equation,
and sub it into the other equation,
We can now multiply this out and solve for x,
Sub back into original equations to check:
So one number is 3 and the other number is 4.  


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