1. Linear Models & Rates of Change (Precalculus Review 2) September 9th, 2015

2. I. The Slope of a Line Def: slope = m = y/ x = (y 2 - y 1 )/(x 2 - x 1 ) *slope of vertical lines is undefined

3. II. Equations of Lines Point-Slope Equation of a Line: y - y 1 = m(x - x 1 )

4. Ex. 1: Find the equation of the line that has a slope of -5 and passes through the point (2, -3).

5. III. Ratios & Rates of Change The slope of a line on the x- and y-axes that have equal units of measure is a ratio. When the x- and y-axes have different units of measure, the slope can be interpreted as the rate of change.

6. IV. Graphing Linear Models Slope-Intercept Equation of a Line: y = mx + b slope y-intercept

7. *Other Equations of Lines: 1. General Form: Ax + By + C = 0 2. Vertical Line: x = a 3. Horizontal Line: y = b

8. V. Parallel & Perpendicular Lines Parallel lines have equal slopes (m 1 = m 2 ). Perpendicular lines have opposite reciprocal slopes (m 1 = -1/m 2 ).