1. Math CC7/8 – Be Prepared
On Desk:
Pencil
Calculator
Math Journal
TwMM Learning Log
Learning Log:
HW: p. 46, #5, 8, 14, 16, 18, #39-42
Turn in Review WS #2

2. Tasks for Today Questions on Test?
Mistakes are Powerful!!
Warm Up – Write an equation from 2 points
Finish Lesson 2.2
Lesson 2.3 – Equations for linear functions

3. y = 2x + -3 Warm Up What is the equation?
Write an equation for the line with points (4, 5) and (6, 9)
(x1,y1) (x2, y2)
What tool can we use to solve for the slope?
The slope algorithm!
(x1,y1) (x2, y2) y2 – y1
x2 – x1
What tool can we use to solve for the y-intercept?
A table!
What is the equation?
y = 2x + -3 X Y
9 – 5
6 – 4
m =
= 4/2 = 2

4. Slope = -1 (x1,y1) (x2, y2) y2 – y1 x2 – x1
This slope is -3 which is less than the other slopes.
(x1,y1) (x2, y2) y2 – y1
x2 – x1
Slope = -1

5. Many possible answers.
(5, 1)
(6, 0)
You could make a table and use the slope to find many different points of the same line.
Yes, they are correct, because a straight line does not change direction or steepness. The ratio of rise over run will be the same no matter what two points you choose.

6. Yes, he is correct!
Using substitution, when x = 1, y = m times 1 = m, and when x = 0, y = m times 0 = 0
Horizontal lines have a slope = 0 (rise is always 0)
Vertical lines have no slope (dividing by a run difference of 0 is impossible)

11. As the number in the group increases by 1, the admission cost increases by $15.
Slope = y-intercept = 60

12. y = 2.5x

13. Decide what the independent and dependent variables are.
Find the unit rate (m, or slope).
Look if the starting value (b) was given.
If not, work backwards to find when x = 0.

14. Find the slope (m)
Finding out the y-value change as x increases by 1.
Use the slope algorithm
Change in y divided by the change in x
Find the y-intercept (b)
Work backwards from the given points to point (0, b) using slope
Use substitution with the slope and a given point (x, y)

15. Find the slope (m)
Find 2 points the line passes through
Use the slope algorithm
Find the y-intercept (b)
Work backwards from the given points to point (0, b) using slope
Use substitution with the slope and a given point (x, y)

16. Dana’s work is correct. In general, if you know the slope of a line and a point on the line you can substitute these three values in for y, m, and x in the equation y = mx + b and solve the equation for b.

17. y = 2x – 3. The equation should be
No, Chris has not used the coordinates of the two points correctly to find the slope.
She put the differences in x on top!
It should be the change in y divided by the change in x, for a slope of 2.