Fundamentals of Math - old

Fundamentals of Mathematics

Graphing: Slope-Intercept Form Another approach (and often quicker) to graphing linear lines is using the slope-intercept form. The slope-intercept form is an equation written in the form

= +

Where is the slope of the line, and is the -intercept. The slope of a straight line shows how steep (the pitch) a straight line is. It's calculated by dividing the change in the height between any two points of a line by the change in the horizontal distance.

Change in Change in

∆ ∆

Slope =

=

− 1 − 1

= 2

2

To graph a line, in slope-intercept form, start by plotting the y-intercept (0, ) . Then use the slope to move up (or down) and over (left or right). Tip: If the slope is an integer (e.g., = −3 + 2 ), turn it into a fraction by dividing it by one (e.g., = −3 1 + 2 ); and move the negative sign to either the numerator or denominator (it doesn't matter which).

Example 4.2.3

= − 2 3

Graph the equation

+ 4 using slope-intercept form.

Step 2: Using the slope find another point of the line. (Go the opposite directions to find the other side of the line.)

Step 3: Connect all your points together using a straight edge.

Step 1: Plot the -intercept.

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