Question

show that the slop of v-u graph represent the acceleration.

Answer 1

let us draw a graph of it
Then
slope=v-u/t ( in velocity time graph)
but as slope is tan theta we can write

Tan theta= v-u/t
tan theta is constant which is equal to A

Answer 2

I think it's v - t graph.
Acceleration is the change in velocity with the time.