Section 7.4Slope-Intercept and Point-Slope Forms of a

Linear Equation

y = mx + b◦m represents the SLOPE (rise/run)

◦b represents the Y-INTERCEPT –> (0, b)

SLOPE-INTERCEPT FORM

1. y = -x + 5 2. 3x + y = 4

3. 16y = 8x + 32 4. -x + 2y = 8

Given the equation, state the slope and the y-intecept:

Find where the line crosses the y-axis. This is the y-intercept, b.

Select 2 points on the line and COUNT for slope using Rise . This is m.

Run Plug m and b into y = mx + b

Writing the equation from the graph:

1) 2x + 3y = 1 and y = -2 x + 3 3

2) 8x + 2y = 10 and x – 7 = 4y

3) 5x – 6y = 18 and -6x + 5y = 10

Are the two lines parallel , perpendicular, or neither?

See graph paper

Ex: Write the equation

1. Rearrange into slope-intercept form if needed.

2. Identify the y-intercept (0, b) and plot it.

3. Beginning at b, move Up and Down, then to the Right for the slope (Rise/Run).

4. Connect the points with a straight line.

To Graph using Slope-Intercept form:

1. 2x + 3y = 6

2. -2x + 5y = 10

Graph

Used to write the equation of a line when you are not given its graph.

y – y1 = m(x – x1)◦m represents the slope◦x1 and y1 represent coordinates from an

point on the line◦Simply plug in the m, x1, and y1 – then

rearrange into slope-intercept form

Point- Slope Form

1. Slope = 3, through (0, -1)

2. Slope = 2/3, through (3, 6)

3. Through (-6, -2) and (5, -3)

4. Through (3, 0) and (-3, 5)

Write the equation of the line with the given properties: