Finding the Equation of a Line

Critical Thinking Skill:

Explicitly assess information and draw conclusions

Three Ways to Write a Linear Equation:

1. Standard Form

2). Slope-Intercept Form

3). Point-Slope Form

Review:Slope intercept form: y= mx + b

 m= slope b = y-intercept

1.) Write the equation of the line that has a slope of -2 and a y-intercept of 5.

2.) Write the equation of the line shown in the graph below

Writing Equations in Slope Intercept form

(2,0)

(0,-4)

Write the equation of the line that passes through the point (6,-3) and has a slope of -2.

 Step 1: Substitute the slope, m and the coordinates of the given point (x,y) into the slope-intercept form.

 y= mx + b

Step 2: Solve for b

Step 3: Substitute the slope and y-intercept back into the slope intercept form

A: Given slope (m) and a point (x,y)

1: m = 8 ( 3, 4)

2: m = 5 ( 4, 2)

Write the equation of the line that passes through the given point and has the given slope.

B: Given two points

ex 1: ( 5, 3) ( 3, 4)

Steps: 1). Find m (use the slope formula)1). y = mx + b2). plug in m, and either point to find b. 3). Re-write the equation with m and b plugged in.

ex 2: ( 8, 2) ( 2, 6)

3.) (2,-2) and (6,0)