Day 5

Daily Objective: Students will be able to write a equation of a line given two data points.
Definition: Student will be able to find the slope and y-intercept to create an equation for two data points.
Step 1: use the equation below to find the slope ( m = slope in the equation y = mx + b)

  

Step 2: substitute x and y in the equation y = mx + b as well as the slope you solved for (m).

Step 3: Solve for b, the y-intercept and use that number and your slope to write out an equation. 

Example: y = 7x + 3

QUIZ

Write an equation using the following data points.

1) (3, 2) (7, -4)

2) (3,2) (7,4)

3) (4,2) (3,6)

ANSWERS

1) y = -3/2x + 13/2

-4 - 2 = -6 over 7 - 3 = 4

Reduce - 6/4 to - 3/2

y = - 3/2x + b

2= - 3/2(3) + b

b = 13/2

Final equation is y = -3/2x + 13/2

 

2) y = 1/2x + 1/2

4-2=2

7-4=3

slope (m)= 2/3

2=2/3(3) + b

b= 1/2

Final equation is y = 1/2x + 1/2

 

3) y = -4x + 18
6-2=4
3-4=-1
slope (m) = -4
2= -4 (4) + b
b= 18
Final equation is y = -4x + 18