You can put this solution on YOUR website!
Any squared term is a parabola... In this case it begins at zero, because you don't have a negative time
Treat your x axis as the t in this case, plug in a couple of numbers for the first equation:
If t=0, y = 0 (Plot (0,0))
If t=1, y = 4 (Plot (1,4))
Connect these two with a curving line (like the bottom of a bowl)
the second equation begins at 2 seconds and will be shaped like an upside down bowl
If t=2, then y=-48 (plot 2,-48)
If t=6 then y=16 (plot 6,16)
The third one will have the same shape as the first: a parabola opening upward, extending to the right:
If t=6 then y=16 (plot(6,16))
If t=8 then y=0 (plot (8,0))
You can always just plug more numbers into your equation if you are unsure of the shape of it.