Transcript 3_6 Clearing fractions and decimals

3.6 Clearing an Equation of
Fractions and decimals
To Clear Fractions
• Multiply every term by the LCD and cross
cancel
Example 1: What number are we
going to multiply by? (LCD)
2
1
5
x  x   2x
3
2
6
2
1
5
x
x
 2x
3
2
6
4 x  3x   5  12 x
 7 x  7 x  5  12 x  7 x
 5  0  5  5x  5
 5  5x
1

x
5
5
Example 3: What is the LCD?
g 2 3
   2g
3 5 2
30 1g 30 2 30 3 30 2 g
      
1 3
1 5 1 2 1 1
10
6
15
30 1g 30 2 30 3 30 2 g
      
1 3 1 5 1 2 1 1
1
1
1
10 g  12  45  60 g
10g +12 =45 -60g
+60 g
+60 g
70 g + 12 = 45
-12 -12
- Add 60g to both sides
to get the variables on
the same side
- Subtract 12 from both
sides to get the numbers on
the same side
70 g = 33 - Divide both sides by
70 to solve for g
70
70
g= 33/70
To Clear Decimals…….
• Multiply every term in the equation by either:
10, 100, 1,000, 10,000, etc.
Key
•
•
•
•
Tens spot multiply by 10
Hundredths spot multiply 100
Thousandths spot multiply by 1,000
Ten thousandths spot multiply by 10,000
• Remember to multiply every term by the
same number!!!
1. 0.8 a + 0.2 = 0.4 a + 0.7
A =5/4
2. 26.45 = 4.2x +1.25
• X=6
Assignment:
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