1. TGIF, Sept. 26, 2014
Today:
Make-Up Tests Now
Warm-Up
Test # 2: Grades & Review
Equations: Old & New
Class Work
Khan Academy Due Sunday: 7:00 pm
2. Warm-Up: (3)
-26
2
5
1
2
m 2
m
3
5
Writing & Solving Equations:
a. Think constant and variable
b. The total is usually given; some combination of variable &
constant will equal the given total.
You need to hire an electrician. He charges a one-time $50.00 fee
and $35.00 per hour.
1. Write an equation and solve to show the cost of hiring the
electrician for 9 hours.
2. If you have $1000 to spend, what is the maximum number of
hours you could hire the electrician?
3. Post-Test: 5 Most Missed
39% V. 1, Q 1
1) .3x + .3 = .6x + .7 - .5x
A) .32 B)15 C) 2 D) .4 E) None
34% V. 3, Q 9
The first stage of a rocket burns 28 seconds longer than the second stage. If
the total burning time for both stages is 182 seconds, how many seconds
does the first stage burn for?
A) 124 B) 77 C) 98 D) 90 E) 105
32% V. 1, Q 8
- 6 = x -
ퟒ
ퟓ
(3 – x) A) 1
ퟏ
ퟒ
B) -3 C)
ퟑ
ퟒ
D)
ퟐ
ퟓ
E) -2
4. Post-Test: 5 Most Missed
30% V. 2, Q 5
4(2x – 2) = -8(x – 4)
The Most Difficult Question was.....
A) 2
ퟏ
ퟐ
B) 2 C) -2 D)
ퟑ
ퟒ
E) No Solution
ퟓ
ퟐ
= .....
26% V. 3, Q10
The sum of three consecutive even numbers is 132.
What is the largest of the three numbers?
A) 33 B) 44 C) 42 D) 46 E) 43
5.
6. Review: Literal Equations
The process of solving a formula for a given variable is
called "solving literal equations".
If someone is ‘Literate’, then they are able to do what?
Reading is simply the decoding of letters. Literal
equations can have many variables, or letters, in them.
Solving literal equations is another way of saying
"take an equation with lots of variables, and solve
for one specific variable.”
To solve literal equations, you do what you've done all
along to solve equations, except that, due to all the
variables, you won't necessarily be able to simplify your
answers as much as you're used to doing.
7. Solving for a Variable
Whatever variable is being solved for must be
isolated on one side of the equation
1. Solve 3m - n = k: for m
2
a. Multiply each side by 2: 3m - n = 2k
b. Add n to each side: 3m = 2k + n
c. Divide each side by 3: m = 2k + n
3
2. Solve for y; 4x – 5y = 7
8. Review: Literal Equations
=
=
SR + TR = U; for R
Hint: Factor
R = __ U__
(S + T)
MN = P – MR; for M
M = __U__
(N + M)
Find the exact temperature in Fahrenheit:
9. Last Slide: Using the Distance Formula
If you drive for 2 ½ hours and average 50 miles per hour,
how many miles have you driven?
D = RT;
2.5•50 = 125 miles
If your average rate of speed is 60 miles per hour, how far
can you travel in one minute? 1 mile
If you drive 175 miles in 2 ½ hours, what is your average
speed?
R =
푫
푻
175/2.5 = 70 mph
A 180 mile trip at 60 mph, would take how long?
T =
푫
푹
180/60 = 3 hours
