Area under graph does give u the answer. I'm not sure whether it
is allowed, although I think it should be unless the question
specifically states that differentiation and integration must be
used.
If you use the graph method:
Just take note that the intercept of the x-axis (time) is the time
for the turning point of the particle. It is the point at which the
velocity is zero. The area after this point will be a negative if
you do normal integration because the particle is now travelling
backwards. However, we are concerned with distance here, and hence
u will need to take the positive value, and add it to the area
above the x-axis before this intercept.
