1. Bellwork
Find the slope of the line containing the points (-1,12) and (5,-6).
Find the product of the slope and y-intercept for the line y=-5x+7.
Write the equation in slope-intercept form for the line that has a y-intercept of 0 and a slope of -1.
Does the table below represent a linear relationship? x 2 3 4 5 6 y
-24
-18
-14 -4 -2

2. Lesson 1.3 Linear Equations in two variables
Algebra 2
Lesson 1.3
Linear Equations in two variables

3. Objectives:
Write a linear equation in two variables given sufficient information.

4. Key concept:
Write an equation in slope-intercept form for the line containing the points (4,-3) and (2,1).
1st: find the slope
m = 1 – (-3) = 4 = -2
m= -2
2nd: find the y-intercept
y=mx + b
1 = -2(2) + b
1 = -4 + b
5 = b
3rd: Write the equation
y=-2x +5

5. Try These: Answer: y = -x - 2
DIRECTIONS: Write an equation in slope intercept form for the line that has the given points.
1.) (1,-3) and (3,-5)
Answer: y = -x - 2
2.) (8,-3) and (-8,3)
Answer:

6. Key concept: Point-slope form y-y₁= m(x-x₁)
EXAMPLE: Write an equation in slope intercept form for the line that has a slope of ½ and contains the point (-8,3).
y – 3 = ½(x- -8)
y – 3 = ½x + 4
y = ½x + 7

7. Try These: Answer: y = -⅔x - 1
DIRECTIONS: Write an equation in slope intercept form for the line that has the given slope and contains the given point.
1.) slope = -⅔ and point (6,-5)
Answer: y = -⅔x - 1
2.) m=0, (-7,8)
Answer: y = 8

8. Homework
Lesson 1.3
Page 26
(10-30 EVENS)