00:01
We're looking at supply and demand here at a given price.
00:05
If we let x be price, y is demand quantity, and z is supply quantity.
00:15
We're told that the relationship between price and demand, or price and supply, are linear.
00:25
So y will be of the form mx plus b, z will be of the form mx plus c.
00:34
Let's see, supply and slope here is demand.
00:41
We're given several data points.
00:43
When x is 80, y equals 865, and z is 480.
00:52
When price is 150, supply or demand is 515, and supply is 900.
01:04
So slope of the demand line is y2 minus y1 over x2 minus x1 is 515 minus 865 over 150 minus 80, which is negative 5.
01:28
Slope for supply line is z2 minus z1 x2 minus x1, and that is 900 minus 480 over 150 minus 80, 420 divided by 70 is 6.
01:50
Then we have y minus y1, 865, is equal to slope, negative 5, times x minus x1...