If you have a graph and want to find the equation for the line, sometimes the y-intercept is not an integer and it is hard to find the equation. Similarly, you can't really find the equation in general form if you only have the graph.
The slope-point form of the equation of a line is the most useful as it only requires the slope and ANY coordinate on the line.
y-y1 = m(x-x1)
Furthermore, it is easy to convert slope point form into both y-intercept and general forms.
- Review of the 3 forms for the equation of a line
- P377 #1-3(ac) #4, #5-6(ac) #7, 8, 10, 11, #13, 15, 16, 17, 22, *19, 20
After today's lesson, you should be able to:
- convert between all 3 forms for the equation of a line (slope-intercept, general and slope-point)
- Graph a line given the equation in slope-point form
- Write the equation of a line in slope-point form if you are given:
- two coordinates
- a coordinate and a slope