The number of taxi accidents is approximated by y equals negative 143.3 x squared plus 1823.3 x plus 6820 and the number of injuries is approximated by y equals negative 416.72 x squared plus 4416.7 x plus 8500. let xequals0 represents 1990, xequals1 represents 1991, and so on.

number of taxi accidents = 12235.2 which is approximately approximately 12235 accidents

Explanation:
The equation for the number of accidents is given as:
y = -143.3 x² +1823.3 x + 6820

We are given that:
x = 0 represents 1990
x = 1 represents 1991
Therefore:
x = 8 represents 1998

Now, all we have to do is substitute with the value of x = 8 in the equation of accidents to get the number of taxi accidents in 1998 as follows:
y = -143.3 (8)² +1823.3 (8) + 6820
y = -143.3 (64) + 1823.3 (8) + 6820
y = -9171.2 + 14586.4 + 6820
y = 12235.2

If we are asked to approximate the answer, then it would be approximately 12235 accidents

Hope this helps :)