Transcript Slide 1

Do Now 1/26/10
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Take out HW from last night.
 Text p. 249, #12-32 evens
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Copy HW in your planner.
 Text p. 256, #14-38 evens
 Quiz sections 5.4 -5.7 Friday
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In your notebook, explain what steps you
would take in order to solve the following
equation. Then solve.
5 2
5
 x 1
14 7
42
x2
2
3
Homework
Text page 249, #12-32 evens
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12) 40
14) -48
16) -1 1/3
18) -1 2/5
20) 11 2/3
22) 33
24) -1/4
26) 2/3
28) 31/35
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30a) 5/8 square inches
30b) 3/4x
30c) 5/8 + 3/4x = 1;
x = 1/2 inch
32a) 1/5
32b) 3750 spectators
32c) 1000 home team fans
11
4 1
 x 
15
5 3
Remember this???
11
4  4  15 412
 x      
15
5  5  15
3 515
Subtract 4/5 from each side.
Write fractions using LCD
7
 15  11
  x  
15
 11  15
 15 
 
 11 
Multiply each side of the equation by the
MULTIPLICATIVE INVERSE of -7/15
1x 
 7   15 -1


15  11 
1
7
x
11
Multiply
Divide (cancel)
common factors
To solve equations with
fractions, so far you
followed these steps:
(1) Undo addition and/or
subtraction to get the
variable alone on one side
of the equation.
(2) Multiply both sides of
the equation by the
multiplicative inverse of
the variable term.
Objective
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SWBAT use the LCD to solve equations and
inequalities.
Section 5.7, “Equations and Inequalities
with Rational Numbers”
**Another way to solve an equation with fractions
is to clear fractions by multiplying the WHOLE
EQUATION by the LCD of the fractions.
The resulting equation is equivalent to the original
equation WITHOUT fractions.
Solving Equations by Clearing Fractions
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4 1
 x 
15
5 3
15
4 1
 11

x

 

5 3
 15
15
11
 x
15
15
Find LCD of all fractions in the
equation, then multiply the whole
equation by the LCD.
4
 
5
 11 x  12  5
15
 11x  7
x
Use distributive property and simplify
each term of the equation.
Two-step equation. Solve for x.
11x  12 12  512
 11
7
x
 11
 11
1
3
7
11
Try It Out!!
Solve
1
7 4
x

2
10 5
2 3
1
  x
9 4
6
10
7 4
1
x

 

10 5 
2
5x  7  8
36
2 3
1
  x
9 4
6
 8  27 x  6
1
x
5
2
x
27
Solving Equations by Clearing Decimals
2.3  5.14  0.8m
Look for the greatest number of decimal
places. Then multiply the WHOLE
EQUATION by that power of 10.
100 2.3  5.14  0.8m
100 2.3 100  5.14 100  0.8m
230  514  80 m
230(514)  514 514  80m
 284  80 m
 284 80 m

80
80
m  3.55
Use distributive property and
simplify each term of the equation.
Two-step equation. Solve for m.
Try It Out!!
Solve
7.8 y  6  23.16 100 7.8 y  6  23.16
780y  600  2316
2  6.4 z  10
y  2.2
10 2  6.4 z  10
20  64 z  100
z  1.25
Solving Inequalities by Clearing Fractions
3
1
1
 x 
4
8
4
8
Find LCD of all fractions in the
inequality, then multiply the whole
inequality by the LCD.
1
1
 3

x





4
8
4


8
3
 x
4
8
1
 
8
8
 6 x  1  2
1

4
Use distributive property and simplify
each term of the inequality.
Two-step inequality. Solve for x.
 6 x  1 1  2 1
 6 x  1
6
1
x
6
6
Don’t forget to flip the
inequality when dividing by a
negative.
1
x
6
Try It Out!!
Solve
1
2
x  14 
5
9
1
53 6
x

7
56 7
45
2
1
x

14



5
9


9 x  630  10
56
1
53 6
x

7
56 7
8 x  53  48
8
x  68
9
5
x
8
Homework
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Text p. 256, #14-38 evens
Homework
Punchline worksheet #79 and practice worksheet 5.6 Form
B evens
Practice worksheet 5.6 B evens
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2) 22
4) 30
6) 38
8) 1 3/4
10) -11/24
12) -5/14
14) 35
16) -36
18) 22
20) -1/5
22) -1/6
24) 1/10
26) 80 days
Punchline worksheet #79
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Flu Shot: A JAB WELL DONE
Fourth of July: JUST UNDER
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