2. Let $\alpha, \beta$ be the roots of the quadratic equation $x^{2}+(p-2) x+1$ $=0$ and. $[1+\alpha(p+\alpha)-\beta][1+\beta(p+\beta)$ $-\alpha]=-\frac{7}{2}$, find the value of $p$.

(Answer: $-\frac{1}{2}$ or $\frac{9}{2}$ )