Here's the problem:
Problem: Recall that you can use two points on a line to determine an equation for the line. Suppose two points in a coordinate plane have coordinates (x1, y1) and (x2, y2).
Alright, I know this is . No problem there.
A. Write a formula that gives the slope b of the line containing the two points.
I don't quite remember how to do this. In the end, I got Please correct me on this.
B. Solve the equation for in Part a for y1 in terms of the other variables.
This is the part I thought was a brain teaser/tongue twister. What do you do here?
C. In your equation from Part b, replace the point with coordinates (x1, y1), with a general point (x, y) on the line. Explain how this equation is now that of a line with slope b through the point (x2, y2).
I don't have the equation for C. yet, so I'll wait for help on that first. :)
D. Use your equation from Part c to write the equation of the line that contains the points (8, 12) and has slope -2. What is the y-intercept of this line?