We have the equation:

let's write in the standard form to identify the values of the constants:

from this we notice that a=1, b=-12 and c=36. Plugging this values into the discriminant we have:

Since the discriminant is equal to zero that means that the equation has only one solution of multiplicity 2.
Let's find the solution with the general formula; plugging the values of a, b and c we have:
![\begin{gathered} y=\frac{-(-12)\pm\sqrt[]{(-12)-4(1)(36)}}{2(1)} \\ =\frac{12\pm\sqrt[]{0}}{2} \\ =(12)/(2) \\ =6 \end{gathered}](https://img.qammunity.org/2023/formulas/mathematics/college/igcnt9h85bswhs7hs28oypd5v5aoedvyp5.png)
Therefore the solution of the equation is 6.