Equation of Horizontal Line y = a number (where it crosses y-axis)
Equation of Vertical Line x = a number (where it crosses x-axis)
Letter that is slope m
Letter that is y-intercept b
Point-Slope Form of Equation of LIne y - y1 = m(x - x1)
Slope Formula m = (y2 - y1) / (x2 - x1)
Slope Intercept Form of Equation of Line y = mx + b
Slope of Horizontal Line Zero
Slope of Vertical Line
Undefined
Slopes of parallel lines.
... ... are the same slope
Slopes of perpendicular lines
... ... have opposite reciprocal slope (one is +, one is - AND they are reciprocals)
Standard Form of Equation of Line