12. For the equation $x^{2}+(2 m-1) x+(m-6)=0$, one root is no greater than -1, and the other root is no less than 1.
(1) Find the range of values for $m$;
(2) Find the maximum and minimum values of the sum of the squares of the roots.
(Solution: $-4 \leqslant m \leqslant 2$; the maximum value is 101, the minimum value is $\frac{43}{4}$.)
