The maximum value of $\left\{x \in \mathbf{R} / \sqrt{x+2}>\sqrt{8-x^2}\right\}=$

$p$ and $q$ are two roots of the equation $x^2+7 x+3=0$. If $\frac{3 p}{1-2 p}, \frac{3 q}{1-2 q}$ are the roots of $l x^2+m x+n=0$ and the greatest common divisor of $l, m, n$ is 1 , then $l-m+n=$

If the quadratic equations $3 x^2-7 x+2=0$ and $k x^2+7 x-3=0$ have a common root then the positive value of $k$ is

If the roots of $x^3+a x^2+b x+c=0$ are in arithmetic progression with common difference 1 , then