I believe it is 805.2. It is not 671
Well, let's take a peek at the graph of that line, hmmm let's pick two points, heck, those tow on the extremes anyway, and those are (-5,2) and (5,-1), alrite.. now, let's do some checking on that.

Answer:
$7.50
Step-by-step explanation:
16/21 is your answer
You can take a 2 out of both numbers to get your answer
I hope this helped! :)