What does the given structural formula represent?

$\sum_{n=1}^{\infty} \frac{2n^2+n+1}{n!}$ is equal to

$A$ centigrade and a Fahrenheit thermometer are dipped in boiling water. The water temperature is lowered until the Fahrenheit thermometer registers $140^{\circ}F$. What is the fall in temperature as registered by the centigrade thermometer in $^{\circ}C$?

The equation $8 x^2-24 x y+18 y^2-6 x+9 y-5=0$ represents a

As the mass number $A$ increases,which of the following quantities related to the nucleus does not change?

$A$ police party is moving in a jeep at a constant speed $v$. They see a thief at a distance $x$ on a motorcycle which is at rest. The moment the police see the thief,the thief starts moving with a constant acceleration $a$. Which of the following relations is true if the police are able to catch the thief?