Bellwork Sketch the following line using point-plotting: 1.) y + x = 5 -2 3

Look at the sheet of topics for this chapter. Decide if we have talked about the given topic. If we have talked about it, determine if you think you know it or not. Each day we will be looking at this sheet to see which topics we will be addressing that day in class.

9.) Write a linear equation in slope-intercept form. 1.) Identify linear functions and linear equations. 2.) Graph linear functions that represent real-world situations and give their domain and range. 3.) Find x- and y-intercepts and interpret their meanings in real-world situations.  4.) Use x- and y-intercepts to graph lines. 5.) Find rates of change and slopes. 6.) Relate a constant rate of change to the slope of a line.  7.) Find slope by using the slope formula.  8.) Identify, write, and graph direct variation.  9.) Write a linear equation in slope-intercept form.  10.) Graph a line using slope-intercept form.

Slope-Intercept Form

Slope-Intercept Form of a Line The equation y = mx + b is the slope-intercept form. m is the slope (think of slope as rise over run) b is the y-intercept An intercept is where the line crosses an axis.

If given the equation, you can identify the slope and y-intercept. Example: In the equation y = 2x + 3, my slope is 2 and my y-intercept is 3. If given the slope and y-intercept, you can write the equation. Example: m = ½ and b = -3 y = ½ x – 3

Graphing Using Slope-Intercept 1.) Identify your slope and y-intercept 2.) Plot your y-intercept by counting up or down b on the y-axis (positive or negative) 3.) Starting at that point (b), use slope to “rise over run” to a 2nd point. 4.) Connect the points.

Example: y = ½ x + 3

Example: y = 2x – 4

Example: y = -¼ x + 3

Try: y = 3x + 2

To write in slope-intercept form, solve for y and then rearrange the terms as necessary. Rewrite in slope-intercept form:

Writing Linear Equations in Slope-Intercept Form

When given a slope and y-intercept… If given the slope and y-intercept, you can write the equation. Example: m = ½ and b = -3 y = ½ x – 3

Try: Write in slope-intercept form: The slope is 3/2; the y-intercept is 3. The slope is 0, the y-intercept is 4.

When given the graph, identify the slope and y-intercept When given the graph, identify the slope and y-intercept. Then, write the equation as you did before. y-int: _____ slope: ______ equation: ______________

Try: y-int: _____ slope: ______ equation: ______________

Writing Linear Equations Given the Slope and a Point

You can write an equation in slope-intercept form by plugging in for m, x, and y to find b. Example: Write an equation in slope-intercept form for the line with slope of ¼ and passes through (8, 3).

Example: Write an equation in slope intercept form given m = ¾ and passes through (2, 3)

Try: Write an equation in slope-intercept form that is horizontal and passes through (4, 3)