slope of that line would be
(0-6)/(3-0) = (-6)/3 = -2
then slope intercept form is
y = mx + b
where m = slope and b is the y intercept
so now we have y = -2x + b
and the y intercept is when x = 0
so b = 6 from that point (0,6)
so we have the equation
y = -2x + 6
which is option C
