Transcript Solving Equations Using Multiplication and Division

Do Now 10/15/10
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Take out HW from Friday.
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Copy HW in your planner.
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Text p. 84 Brain Game “Word Scramble”
Text page 99, #8 – 32 evens
Be ready to copy Problem of the Week #1 for the 2nd
Marking Period.
Homework
Brain Game text p. 84
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8·1=8
3·9=9·3
(2 + 5) + 3 = 2 + (5 + 3)
4x + y = y + 4x
5(7c) = (5 ·7)c
xy + 0 = xy
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Identity
Commutative
Associative
Commutative
Associative
Identity
E
D
N
S
O
Z
“What word has six letters but when you subtract one, twelve remain?”
DOZENS
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 2.6 “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
Homework
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Text page 99, #8 – 32 evens
WAR!!!
Using your boards solve the
equations as fast as possible.
If your number is called … you
are at WAR!!