Question 53000
x=100 items [Identify the independent variable (x)]
y=10,000 [Identify the dependent variable (y) that changes depending upon (x)]
Coordinate points (100; 10,000)
.
x=300 items [Identify the independent variable (x)]
y=$22,000 [Identify the dependent variable (y) that changes depending upon (x)]
Coordinate points (300; 22,000)
.
Slope = m = (y2-y1)/(x2-x1) [Formula for the slope of a line]
m=(y2-y1)/(x2-x1)
m=(22,000-10,000)/(300-100) [Plug-in the values]
m=60
.
y=mx+b [Slope-intercept form of a line]
22,000=(60)(300)+b 
22,000=18000+b
b=4000
y=60x+4000
C(x)=60x+4000
.
.
Driving down a mountain, Tom finds that he has descended 1800 ft in elevation by the time he is 3.25 mi horizontally away from the top of the mountain. Find the slope of his descent to the nearest hundredth.

.
Slope = m = rise/run=-1800/3.25=-553.85