7.
[tex]dla \ \ x = -\frac{1}{3} \ \ i \ \ y = -\frac{1}{2}\\\\\\12x^{2}-12y^{3} =12\cdot(-\frac{1}{3})^{2} - 12\cdot(-\frac{1}{2})^{3} = 12\cdot\frac{1}{9} -12\cdot(-\frac{1}{8}) = \frac{12}{9}+\frac{12}{8} = \frac{4}{3}+\frac{3}{2} =\\\\= \frac{8}{6}+\frac{9}{6} =\boxed{\frac{17}{6}}\\\\\underline{Odp. \ C}[/tex]