Ch. 3.1 continued
Solving an equation with negative coefficients:
EXAMPLE 1
EXAMPLE 2
Solve: 7 – 4y = 19
Solve 12 – 4s = -12
7 – 4y = 19
-7
-7
-4y = 12
-4 -4
y = -3
12 -4s = -12
-12
-12
-4s = -24
-4
-4
s=6
EXAMPLE 3
5 – X = 198
EXAMPLE 3
-4 + 3m = 29
+4
+4
3m = 33
3
3
m = 11
6 – 2m = 8
-2 = 5 - n
20 – 12m = 44
– 2y + 11 = 31
Word problems involving two-step equations
You are buying a drum set that costs $495. The music store lets you make a down
payment. You can pay the remaining cost in three equal monthly payments with no
interest charged. You make a down payment of $150. How much is each monthly
payment?
What is the important information?
• Costs $495
• Down payment of $150
• I have 3 months to pay remaining
amount ($495 - $150)
Set up your equation:
150 + 3p = 495
Solve:
150 + 3p = 495
-150
-150
3p = 345
3
3
p = 115
Word problems involving two-step equations
You go to a local candy store to purchase some rock candy and chocolate bars. You
have a total of $5 in your pocket to spend. If you purchase one bag of rock candy for
$1.75, how many chocolate bars can you purchase if each chocolate bar costs $1.50?
Homework
Page 123 #’s 5-6, 15-22, 28, 32-33, 46