Answer:
The car must have a speed of 25 kilometres per hour to stop after moving 7 metres.
Step-by-step explanation:
Let be 
, where 
is the stopping distance measured in metres and 
is the speed measured in kilometres per hour. The second-order polynomial is drawn with the help of a graphing tool and whose outcome is presented below as attachment.
The procedure to find the speed related to the given stopping distance is described below:
1) Construct the graph of 
.
2) Add the function 
.
3) The point of intersection between both curves contains the speed related to given stopping distance.
In consequence, the car must have a speed of 25 kilometres per hour to stop after moving 7 metres.
To get for the taxi accidents in 1998, we must note that x =
8. Therefore using the equation y=−143.3x2+1823.3x+6820 , we can
calculate for the number of taxi accidents.
y = -143.3 * (8)^2 + 1823.3 * 8 + 6820
y = 12,235.2
There were about 12,235 taxi accidents in 1998.
