What is common in the two graphs given below?

$A$ particle moves according to the equation $x = a + bt^2$,where $a = 15 \, cm$ and $b = 3 \, cm/s^2$. What is the velocity of the particle at $t = 3 \, s$ in $cm/s$?

The displacement $x$ versus time graph is shown below. Analyze the following statements:
$(A)$ The average velocity during $0$ to $3\ s$ is $10\ m/s$.
$(B)$ The average velocity during $3$ to $5\ s$ is $0\ m/s$.
$(C)$ The instantaneous velocity at $t = 2\ s$ is $5\ m/s$.
$(D)$ The average velocity during $5$ to $7\ s$ and instantaneous velocity at $t = 6.5\ s$ are equal.
$(E)$ The average velocity from $t = 0$ to $t = 9\ s$ is zero.
Choose the correct answer from the options given below.

$A$ particle moves along $X$-axis in such a way that its coordinate $x$ varies with time $t$ according to the equation $x = (2 - 5t + 6t^2) \ m$. The initial velocity of the particle is ....... $m/s$.

What does the area of $v-t$ graph of a moving object represent?

The slope of the velocity-time graph for motion with uniform velocity is equal to: