1. 1. Set-up notes. Topic is “writing equations of lines in slope-intercept form”
2. Example 1: Write the equation of the line, in slope-intercept form, that passes through (3, 5) and (5, 9)
3. Plot (3, 5) and (5, 9) on a graph paper square and paste in your note book. Using your graph, write the equation of the line.

2. y = mx + b y = mx+ b is an equation that defines a line
A line has two characteristics:
1.) Slope
2.) Points that fall on the line
To write the equation of a line, you need:
1.) The slope of the line
2.) ANY point on the line

3. Ex1:
Write the equation of the line, in slope-intercept form, that passes through (3, 5) and (5, 9)
m = (y2-y1)/(x2-x1)
Step 1: Find the slope
m = (9-5)/(5-3) = 4/2 = 2
Step 2: Plug in either coordinate into y = mx + b and solve for b
(3, 5) (5, 9)
y = mx + b y = mx+b
5 = 2(3) + b OR 9 = 2(5) + b
5 = 6 + b = 10 + b
-1 = b = b
Step 3: Write the equation of the line by substituting the values you computed for m (step 1) and b (step 2) in y = mx + b
y = 2x – 1
Besides (3, 5) and (5, 9), list 5 other points on this line.

4. Ex2:
Write the equation of the line, in slope-intercept form, with a slope of 10 that passes through (-1, -4)
m = 10
Step 1: Find the slope
Step 2: Plug in either coordinate into y = mx + b and solve for b
(-1, -4)
y = mx + b
-4 = 10(-1) + b
-4 = b
6 = b
Step 3: Write the equation of the line by substituting the values you computed for m (step 1) and b (step 2) in y = mx + b
y = mx + b
y = 10x + 6
Besides (-1, -4) list another point on this line.

5. 1. Consider the points (3, 7), (-6, 1) and (9, p) on the same line
1. Consider the points (3, 7), (-6, 1) and (9, p) on the same line. Write a linear equation to find the value of p.
2. The x-intercept of a line is p, and the y-intercept is q. Write an equation of the line in slope-intercept form.
p = 11
y = -q/px + q 5

6. SWBAT… Write equations in slope-intercept form Tues, 1/4
Agenda
WU (15 min)
Review hw#5 (15 min)
Quiz (15 min)
WARM-UP:
Write the slope-intercept form of an equation of the line that satisfies each condition:
1.) Has slope 3 and y-intercept -5
2.) Passes through (5, -7) and has a slope of 3
3.) Passes through (6, -3) and (12, -3)
4.) Has an x-intercept of -2 and a y-intercept of 4 (Hint: write the two points)
2 problems
1. y = 3x – 5
2. y = 3x – 22
3. y = -3
4. y = 2x + 4 (the two points are (-2, 0) and (0, 4))