CAT (QA) PYQs

$f(x) = \frac{x^2+2x-15}{x^2-7x-18}$ is negative if and only if

Any non-zero real numbers $x, y$ such that $y \neq 3$ and $\frac{x}{y}<\frac{x+3}{y-3}$, Will satisfy the condition.

If $a$ and $b$ are integers such that $2x^2 - ax + 2 > 0$ and $x^2 −bx + 8 \geq 0$ for all real numbers $x,$ then the largest possible value of $2a-6b$ is