Chapter 9 - XYZ Custom Plus

542
Chapter 9 Solving Equations and Inequalities
Equations Containing Decimals
8. Solve: } 1 }x 2 2.4 5 8.3
5
Example 8
Solve: } 1 }x 2 3.78 5 2.52
2
Solution
multiply each side by 2.
We begin by adding 3.78 to each side of the equation. Then we
} 1 }x 2 3.78 5 2.52
2
} 1 }x 2 3.78 1 3.78 5 2.52 1 3.78 Add 3.78 to each side
2
} 1 }x 5 6.30
2
2 1
} 1 2 }x 2
5 2(6.30) Multiply each side by 2
x 5 12.6
9. Solve: 7a 2 0.18 5 2a 1 0.77
Example 9
Solve: 5a 2 0.42 5 23a 1 0.98
Solution
each side.
We can isolate a on the left side of the equation by adding 3a to
5a 1 3a 2 0.42 5 23a 1 3a 1 0.98
8a 2 0.42 5 0.98
8a 2 0.42 1 0.42 5 0.98 1 0.42
8a 5 1.40
Add 3a to each side
Add 0.42 to each side
} 8 a
} 5 } 1. 40 } Divide each side by 8
8 8
a 5 0.175
Getting Ready for Class
After reading through the preceding section, respond in your own
words and in complete sentences.
1. Apply the distributive property to the expression 3(x 1 4).
2. Write the equation that results when 24a is added to both sides of the
equation below.
6a 1 9 5 4a 2 3
1 3
3. Solve the equation 2x 1 } } 5 2 4 } by first adding 2} 1 } to each side.
2
Compare your answer with the solution to the equation shown in Example
6.
Answers
8. 53.5 9. 0.19