Answer
a) $y=-8000x+121000$
b) 89,000 employees
Work Step by Step
a)
$(0, 121000)$ and $(2,105000)$
$m=(121000-105000)/(0-2)$
$m=16000/-2$
$m=-8000$
$y=mx+b$
$121000=0*-8000+b$
$121000=0+b$
$121000=b$
$y=-8000x+121000$
b)
$y=-8000x+121000$
$2011-2007=4$
$y=-8000x+121000$
$y=-8000*4+121000$
$y=-32000+121000$
$y=89000$