4. 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. Try to find:
(1) the range of values for the parameter $m$;
(2) the maximum and minimum values of the sum of the squares of the roots.
(9th Junior High School Mathematics Competition, Jiangsu Province)
(Hint: (2) Convert $x_{1}^{2}+x_{2}^{2}$ into a quadratic function of $m$, then find the maximum and minimum values. Answer: (1) $-4 \leqslant m \leqslant 2$ (2) Maximum value 101, Minimum value $\frac{43}{4}$ )