Solving Equations Using Multiplication and Division

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Do Now 10/17/11
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Take out HW from Friday.
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Copy HW in your planner.
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Punchline worksheet #38
Text p. 74, #4-6, 14-19, 22-34 evens, 43, 44, 48, & 49
Quiz on equations Friday.
Be ready to copy Problem of the Week #6.
Homework
Punchline worksheet 38
“What Do Opticians, Optometrists,
and Opthamologists Have In
Common?”
THEY ALL WENT TO EYE SCHOOL
Objective
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SWBAT use multiplication and division
to solve equations
Equation
mathematical sentence
with an equal sign
Like a scale,
both sides
must be balanced
Equation
2x = 10
Left side
‘x’ has to be 5 in order
to make the equation
balanced.
Like a scale, the left
side and right side must
be the same in order to
be balanced!
Right side
Section 2-5 “Solving Equations Using
Multiplication and Division”
How can you get the “unknown” by itself?
-2y = 28
“Undo” the operation by using the INVERSE
operation to both sides of the equation.
Solving a Multiplication Equation
-2y = 28
-2
-2
y = -14
“Undo”
multiplication
by dividing
both sides of the
equation
Check Your Work! y = -14
-2y = 28
-2(-14) = 28
Are both sides equal?
Try It Out
1). -7t = 63
2). -144 = 12d
3). 10x = 5
1). t = -9
-7(-9) = 63
2). d = -12
-144 = 12(-12)
3). x = ½
10(½) = 5
Solving a Division Equation
5· j = -7 · 5
5
j = -35
“Undo”
division by
multiplying
both
sides of the
equation
Check Your Work!
j = -7
5
-35 = -7
5
j = -35
Are both sides equal?
Try It Out
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1). r ÷ 8 = -2
2). v = 8
4
3). -9 = a
5
1). r = -16
-16 ÷ 8 = -2
2). v = 32
32 = 8
4
3). a = -45
-9 = -45
5
Find the width of the rectangle.
x
2x = 38 cm²
2 Area = 38 cm²
9z = 27 m²
x = 19 cm
9
z Area = 27 m²
z=3m
24
Homework
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Text p. 74, #4-6, 14-19, 22-34 evens, 43, 44, 48, & 49
WAR!!!
Using your boards solve the
equations as fast as possible.
If your number is called … you
are at WAR!!
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