Download lesson 3.6 - Clearin..

6 minutes
Warm-Up
Simplify.
1
1) 3  x
3
1
3

2) 2  y  
2
2
3) 10(1.2u + 0.5)
3.6 Clearing an Equation of
Fractions or Decimals
Objectives:
•To clear an equation of fractions or decimals
Solve.
1
1 3
p 
3
6 2
Example 1
1
1
3
6 p  6  6
3
6
2
6
6 18
p 
3
6 2
2p + 1 = 9
-1 -1
2p = 8
2 2
p=4
The LCD is 6.
Multiply both sides by 6.
Solve.
2 1
1
 x
3 4
3
Example 2
2
1
1
12   12  x  12 
3
4
3
The LCD is 12.
Multiply both sides by 12.
24 12
12
 x
3
4
3
8 + 3x = 4
-8
-8
3x = -4
3 3
4
x
3
Practice
Solve.
7
3 1
3
x  x
1)
8
4 2
2
5
1 2
2) x   x  4
6
2 3
2
2
 3y  5y 
3)
3
15
Example 3
Solve.
0.5r + 1.5 = 3
Multiply both sides by 10
to clear the decimals.
10(0.5r) + 10(1.5) = 10(3)
5r + 15 = 30
-15 -15
5r = 15
5 5
r=3
Example 4
Solve.
0.7x – 15 + x = 2x – 8 – 0.4x
10(0.7)x – 10(15) + 10(x) = 10(2x) – 10(8) – 10(0.4)x
7x – 150 + 10x = 20x – 80 – 4x
17x – 150 = 16x – 80
-16x
-16x
x – 150 = – 80
+ 150 + 150
x = 70
Practice
Solve.
1) 26.45 = 4.2x + 1.25
2) 41.68 = 4.7 – 8.6y
3) 0.7n – 15 + n = 2n – 8 – 0.4n
Homework
p.140 #7-23 odds