The second one because it allows for all the points to be presented
Mitchell because if you add a zero at the end of the .8 it would be 0.80 and 0.75 is smaller than 0.80 so Mitchell has more work to do at home
The slope-intercept form:

<em>add 27x to both sides</em>
<em>divide both sides by 9</em>

To analyze the problem first is to arrange the equations according to their uses:
# of taxi accident y = -143.3X^2+1823.3x+6820
# of injuries y = -416.72X^2+4416.7x+8500
So the answer if X = 9 will be represented by 1999
# of taxi accident y = 11622.4
# of injuries y = 14495.98
I hope you understand the answer and feel free to ask for more.