Explain why the slope ๐ is the same between any two distinct points on a non-vertical line in the coordinate plane; derive the equation ๐ฆ = ๐๐ฅ for a line through the origin and the equation ๐ฆ = ๐๐ฅ + ๐ for a line intercepting the vertical axis at (0, ๐).

Expressions and Equations

Understand the connections between proportional relationships, lines, and linear equations.