Transcript SOLVING ONE-STEP EQUATIONS

SOLVING ONE-STEP
EQUATIONS
DAY TWO
Ms. Turk, Algebra I
Unit 2-1
Solving One-Step Equations
With Multiplication & Division
Multiplication and division are inverse
operations. In other words, they undo
each other. When you solve an equation
involving division, multiply each side of
the equation by the same number.
Example 1: Multiplication
x
 11.4
4
(-4)
x
 11.4
4

(-4)
• Multiply each side of
the equation by -4 in
order to isolate the
variable on one side of
the equation.

x = 45.6
• Simplify.

Example 2: Multiplication
x
 3.4
10
x
(10)
 3.4 (10)
10

x = 34
• Multiply each side of
the equation by 10 to
get the variable on one
side of the equation.
• Simplify.
Example 3: Multiplication
Try one on your own!
m
 2.5
12
m
(12)
 2.5 (12)
12


m = 30
• Did you multiply
both sides by 12?
• Then did you
simplify?
Example 4: Division
5x = 35
5x ÷ 5 = 35 ÷ 5
x=7
• Divide both sides of
the equation by 5 to
isolate the variable
on one side.
• Simplify.
Example 5: Division
10x = 125
10x ÷ 10 = 125 ÷ 10
x = 12.5
• Divide both sides by
10 to get x by itself
on one side of the
equation.
• Simplify.
Example 6: Division
Try one on your own!
6.5x = 195
6.5x ÷ 6.5 = 195 ÷
6.5
x = 30
• Did you divide both
sides by 6.5?
• Then did you
simplify?
Real World Problem Solving
Wages
Suppose you work part-time at the
city library. You earn $145.35 for 19
hours of work. What is your hourly
wage? Write and solve an algebraic
equation to solve this problem.
Real World Problem Solving
• Relate:
• Number of hours worked times
wage equals total earnings.
• Define:
• Let w = wage.
• Write:
• 19 w = 145.35
Real World Problem Solving
19w = 145.35
19
19
w = 7.65
Your hourly wage is $7.65.
Now you try!
Car Repair
Your bill for car repair is $321.00.
One third of the bill is for labor.
Write and solve an equation to
solve for the cost of labor.
Now you try!
• Relate:
• The repair bill divided by three
equals the cost of labor.
• Define:
• Let c = cost of labor
• Write:
•
321 = c
3
Now you try!
321 = c
3
c = 107
The cost of labor is $107.00
Practice Problems
Please take a
few moments to
complete the
following
practice
problems in
your notes.
2x = 17
(8.5)
18x = 70
(3.89)
x/2 = 100
(200)
x/3.5 = 12
(42)
4.2x = 20
(4.76)
Classwork
A. Workbook page 20
22, 25, 27 - 50 all
B. Square Deal Game