I need help to solve this problem:

Two-digit number is three times bigger from sum of digits which that number contains, and square of that sum of digits is equal to triple number which is wanted. Find that number.
I have represented that two-digit number as

Multiplying both sides with (x+y) we get that

Dividing left side with 3 we will get that

which is number that we want.

So I think we must solve system of equation

I have tried to solve this equation by puting

(from first equation) into second equation but the result is x=0 and y=0.

Is my way of solution right?

help to solve.