Помогите пожалуйста g(x)=log0,12(7+6x-x2)

[latex]g(x)=log_{0.12}(7+6x-x^2) \\ D(y):7+6x-x^2\ \textgreater \ 0,\ \ \ \ \ x\in(-1;7) \\g'(x)=(log_{0.12}(7+6x-x^2))'=\frac{6-2x}{(7+6x-x^2)ln0.12}=\frac{2(3-x)}{-(x-7)(x+1)ln0.12} \\Kriticheskie\ tochki: \\\frac{2(3-x)}{-(x-7)(x+1)ln0.12}=0 \\ \left \{ {{2(3-x)=0} \atop {-ln0.12*(x-7)(x+1)\neq0}} \right. \\ \left \{ {{x=3} \atop { \left[\begin{array}{ccc}x\neq7\ (ne\ vhodit\ v \ oblast opredeleniya)\\x\neq-1 (ne\ vhodit\ v \ oblast opredelniy\end{array} }} \right\right \\Kriticheskie\ tochki : x=-1; \\ Grafik\ na\ kartinke[/latex]