Let the point ( p, p +1) lie inside the region E={(x, y): 3-x ≤ y ≤ √(9-x^2), 0 ≤ x ≤ 3}. If the set of all values of p is the interval (a, b), then…

Let the point $\displaystyle (\mathrm{p}, \mathrm{p}+1)$ lie inside the region $\displaystyle E=\left\{(x, y): 3-x \leq y \leq \sqrt{9-x^2}, 0 \leq x \leq 3\right\}$. If the set of all values of p is the interval $\displaystyle (a, b)$, then $\displaystyle b^2+b-a^2$ is equal to $\displaystyle \_\_\_\_$