Transcript Presentation Title - St. Landry Parish School Board

Solving Two-Step Equations
Ex. 1: Solve 4x – 5 = 15
4x – 5 =
+5
4x
=
4
x=5
15
+5 (Add 5 to both sides)
20 (Simplify)
4 (Divide both sides by 4)
(Simplify)
Try These Examples
1. 2x – 5 = 17
x = 11
2. 3y + 7 = 25
y = 6
3. 5n – 2 = 38
n = 8
Ex. 2: Solve x/3 + 4 = 9
x
3
x
3
x
3
+4= 9
-4 -4
(Subtract 4 from both sides)
= 5
(Simplify)
•3
x = 15
= 5 • 3 (Mult. by 3 on both sides)
(Simplify)
Try these examples!
1. x – 3 = 8
5
x = 55
2. c + 4 = 9
7
c = 35
3. r – 6 = 2
3
r = 24
Ex. 3: Solve 6 = 3(a - 5)
6 = 3(a - 5)
6 = 3a - 15
+ 15
+ 15
21 = 3a
3
3
7 = a
(distribute the 3)
(Add 15 to each side)
(Simplify)
(Divide both sides by 3)
(Simplify)
Try These Examples
1. 5(c + 2) = -15
2. h + 3
7
= -2
3. -3(9 + 2b) = 33
c = -5
h = -17
b = -10
Real World Application
Suppose you buy a $1.50 slice of pizza and split the cost of renting a
video with two friends. Your total cost is $2.75. Write and solve an
equation to find the cost of the video rental.
Words
Cost of Pizza
+
(Cost of video ÷ 𝟑)
is
$2.75
=
$2.75
Equation
1.50
+
(v ÷ 𝟑)
Real World Application
Equation
+
1.50
1.50
- 1.50
3
(v ÷ 𝟑)
+
v
3
=
=
v
3
=
$1.25
3
v
$2.75
$2.75
- 1.50
= $3.75
Real World Application
Mary received $100 for her birthday. She then saved $20 a week until
she had a total of $460 to buy an ipad. Use an equation to show how
many weeks it took her to save the money needed.
Words
money received
+
(2𝟎 𝒙 𝐰𝐞𝐞𝐤𝐬)
is
$460
+
(2𝟎𝐰)
=
$460
Equation
100
Real World Application
Equation
100
100
- 100
+
+
20w =
20
(2𝟎𝐰)
=
20w
=
$460
$460
- 100
$360
20
w
= 18
Real World Application
A health club charges a $50 initial fee plus an additional $2 per visit.
Marcus has spent a total of $144 on the health club this year. Use an
equation to show how many visits he has made this year.
Words
Initial Fee
+
(2 𝒙 𝐯𝐢𝐬𝐢𝐭𝐬)
is
$144
+
(2𝐯)
=
$144
Equation
50
Real World Application
Equation
+
50
50
- 50
(2𝐯)
+
2v
2
=
2v
=
=
$144
$144
- 50
$94
2
v
= 47