Chapter 4 of 10All chapters
Chapter 4 of 10
Straight lines
y = mx + c and what it means.
Slope and intercept
m is how much y changes for each unit of x, and c is the value of y when x is zero. Every straight relationship in the world has this form.
- A positive slope rises, a negative slope falls, zero is flat.
- Parallel lines share a slope; perpendicular slopes multiply to -1.
From two points
Slope is the change in y divided by the change in x between any two points on the line. Once you have the slope, one point gives you c.