Section 2.3 Linear Functions: Slope, Graphs & Models  Slope  Slope-Intercept Form y = mx + b  Graphing Lines using m and b  Graphs for Applications  Graph paper required for this and all future graphing exercises. Each graph about 4 inches square. Limit 6 graphs per page. 12.3

What is Slope & Why is it Important?  Using any 2 points on a straight line will compute to the same slope. 22.3

The Dope on Slope  On a graph, the average rate of change is the ratio of the change in y to the change in x  For straight lines, the slope is the rate of change between any 2 different points  The letter m is used to signify a line’s slope  The slope of a line passing through the two points (x 1,y 1 ) and (x 2,y 2 ) can be computed:  Horizontal lines (like y = 3 ) have slope 0  Vertical lines (like x = -5 ) have an undefined slope  Parallel lines have the same slope m 1 = m 2  Perpendicular lines have negative reciprocal slopes m 1 =-1/m

Slope Intercept Form of a Straight Line f(x) = mx + b or y = mx + b  Both lines have the same slope, m =

Using b to identify the y-intercept point (0,b)  the above y-intercepts are: (0,0) and (0,-2)  What’s the y-intercept of y = -5x + 4 (0,4)  What’s the y-intercept of y = 5.3x - 12 (0,-12) 52.3

Calculating Slopes 62.3

Graphing a Straight Line using the y-intercept and the slope 72.3

The Slope-Intercept Form of a Line 82.3

Graphing Practice: 92.3

Lines not in slope-intercept form 102.3

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Next  Section 2.4 Another Look at Linear Graphs Section 2.4 Another Look at Linear Graphs 152.3