Example: Problem 7 shows how to find an equation through points (0,3) and $-4,-1$, resulting in y = x + 3.

Highlight: The page includes a special case of a vertical line $x = -3$ where slope is undefined, demonstrating an important exception to standard slope-intercept form.

Definition: A vertical line has an undefined slope and cannot be written in slope-intercept form. Instead, it is written as x = constant.

Vocabulary: Undefined slope occurs when a line is vertical, as the change in x is zero, making division impossible in the slope calculation.

Definition: The slope-intercept form of a linear equation is y = mx + b, where m is the slope and b is the y-intercept.

Example: In the first problem, students analyze a graph to find y-intercept (100) and slope $8/7$ to write the equation y = $8/7$x + 100.

Highlight: The page demonstrates multiple methods for finding slope, including using coordinate points and calculating rise over run.

Vocabulary: Y-intercept is the point where a line crosses the y-axis, while slope represents the rate of change between any two points on the line.