If $4{\mathrm{a}}^2+9{\mathrm{b}}^2-{\mathrm{c}}^2+12\mathrm{ab}=0$, then the set of lines $\mathrm{ax}+\mathrm{by}+\mathrm{c}=0$  passes through the fixed point

$$\begin{gathered} 4a^2+9b^2+12ab-c^2=0 \\ \Rightarrow {(2a+3b)}^2-c^2=0 \Rightarrow (2a+3b+c)(2a+3b-c)=0 \\ \Rightarrow 2a+3b+c=0 or \Rightarrow 2a+3b-c=0 \\ \therefore ax+by+c=0 passes through the points (2,3) and (-2,-3) \end{gathered}$$