\[y = f(x);\ \ \ y = g(x);\ \ \]
\[где\ \ f(x) = 4x^{2};\ \ \ g(x) = x^{2}\]
\[f(x - 3) = g(x + 6)\]
\[4 \cdot (x - 3)^{2} = (x + 6)^{2}\]
\[4x^{2} - 24x + 36 = x^{2} + 12x + 36\]
\[3x^{2} - 36x = 0\]
\[3x(x - 12) = 0\]
\[3x = 0\ \ \ \ \ \ \ \ \ x - 12 = 0\]
\[x = 0\ \ \ \ \ \ \ \ \ \ \ \ x = 12\]
\[Ответ:\ x = 0;\ \ x = 12.\]