Is the statement 'The slope of a position-time graph can be negative' true or false?

The given graph shows the variation of velocity $(v)$ with position $(x)$ for a particle moving along a straight line. Which of the following graphs shows the variation of acceleration $(a)$ with position $(x)$?

The $x-t$ graph for a uniformly accelerated particle is as shown in the figure. Find the average velocity between points $(i)$ and $(ii)$ in $ms^{-1}$.

The speed-time graph of two cars $A$ and $B$ approaching each other is shown in the figure. The initial distance between them is $60\,m$. The two cars will cross each other after time $..........\,s$.

Which of the following velocity-time graphs shows a realistic situation for a body in motion?

The velocity-time graph of a particle in one-dimensional motion is shown in the figure. Which of the following formulae are correct for describing the motion of the particle over the time-interval $t_1$ to $t_2$?
$(a)$ $x(t_2) = x(t_1) + v(t_1)(t_2 - t_1) + (1/2)a(t_2 - t_1)^2$
$(b)$ $v(t_2) = v(t_1) + a(t_2 - t_1)$
$(c)$ $v_{\text{average}} = (x(t_2) - x(t_1)) / (t_2 - t_1)$
$(d)$ $a_{\text{average}} = (v(t_2) - v(t_1)) / (t_2 - t_1)$
$(e)$ $x(t_2) = x(t_1) + v_{\text{average}}(t_2 - t_1) + (1/2)a_{\text{average}}(t_2 - t_1)^2$
$(f)$ $x(t_2) - x(t_1) = \text{area under the } v-t \text{ curve bounded by the } t\text{-axis and the dotted lines shown.}$