1. Math CC7/8 – April 19 Math Notebook: Things Needed Today (TNT):
Pencil/Math Notebook/Calculators/book
TwMM 2.4
Math Notebook:
Topic: Solving linear Equations
p.49 #20, 21, #22-25 (a only!), #43 & Worksheet Packet (solving word problems with linear eq)

2. What’s Happening Today?
HW ?s
Warm Up – Write an equation from 2 points, slope & a pt, and parallel lines
Lesson 2.4 – Solving linear equations

3. Warm Up Note: parallel lines have the SAME slope (m)
Find an equation for the line that satisfies the conditions.
Note: parallel lines have the SAME slope (m)

4. greater than or equal to
What are inequalities?
Symbol
Words
Example Use =
equals
1 + 1 = 2 ≠
not equal to
1 + 1 ≠ 1
>
greater than
5 > 2
<
less than
7 < 9 ≥
greater than or equal to
marbles ≥ 1 ≤
less than or equal to
dogs ≤ 3

5. What is an inequality? An inequality is similar to an equation.
There are two expressions separated by a symbol that indicates how one expression is related to the other.
In an equation such as 7x = 49, the = sign indicates that the expressions are equivalent.
In an inequality, such as 7x > 49, the > sign indicates that the left side is larger than the right side.
To solve the inequality 7x > 49, we follow the same rules that we did for equations.
In this case, divide both sides by 7 so that x > 7. This means that x is a value and it is always larger than 7, and never equal to or less than 7.

7. What strategies do you find useful to find solutions for linear equations?

8. $ 0.15 = the cost per minute of rental time
Pg. 41
$ 0.15 = the cost per minute of rental time
$2.50 = the fixed charge for renting
buddies/truddies please work on problems #2-3 in your notebook. Solve algebraically and SHOW ALL STEPS. Y our buddy/truddy will check your notebook today!

9. Pg. 41
Solve for t…
$9.25 = 0.15t
6.75 = 0.15t
45 = t
45 minutes to ride the canoe
2. Use substitution!
c = 0.15t
c = 0.15(25)
c =
c = $6.25

10. Hint: Use an inequality!
Pg. 41
$ ≥ 0.15t
3.50 ≥ 0.15t
≥ t or
t ≤ minutes
Hint: Use an inequality!
She can use the canoe for no more than 23 and 1/3 minutes, or about 23 minutes or less.

11. Pg. 39
You can easily estimate the y-intercept. (2.50)
You can use it to calculate the slope. (0.15)
You can find 25 min on the x-axis and estimate the cost from the y-axis.
You can find $9.25 on the y-axis and estimate the time for that charge.
You can use it to find all the times that would lead to a cost of no more than $6.

12. Pg
You can calculate the slope by finding the change in y (rental charge) as x (time) increases by 1 minute. (slope = 0.15)
You could work backwards and find the y value for when x is 0. (y-intercept = 2.50)
You can find the y-value (cost) for 25 min. by finding the point between 20 and 30 on the table.
You can find the time for $9.25 by finding the point between 40 and 50 minutes.
You can find the rental time for no more than $6 by looking at the rental charge row and seeing it would be just over 20 minutes.

13. Pg. 42
Yes, they are correct!
They subtracted 2.50 from each side of the equation and then divided by 0.15 on each side of the equation.

14. Pg. 42
She can use the canoe for no more than 23 and 1/3 minutes, or about 23 minutes or less.

15. c = $6 to rent a paddle boat for 20 minutes
Pg. 42
Solve for t…
$9 = t
5 = 0.10t
50 = t
Use substitution!
c = t
c = (20)
c = 4 + 2
c = $6 to rent a paddle boat for 20 minutes
He used the boat for 50 minutes

16. Hint: Use an inequality!
Pg. 42
Hint: Use an inequality!
$ ≥ t
8 ≥ 0.10t
80 ≥ t or
t ≤ 80 minutes
You can use the paddle boat for no more than 80 minutes, or an hour and 20 minutes or less.