Transcript 2.1 Solving Equations by Adding and Subtracting

2.1 Solving Equations by
Adding and Subtracting
Algebra 1 Book
Pg. 77
Warm Ups
Evaluate
40%
A.
2
1
 4
3
3
40%
2

3
B.
2
3
3
C.
2
6
20%
A.
B.
C.
What is the Additive Inverse?
1. 8
2. 6
1
3.
2
4. - 5
5. 
2
3
Evaluate each Expression
• For (a = 3) and (b = - 2)
1. a + 5
2. 12 - b
Objective
• Solve one-step equations in one
variable by using addition,
subtraction, multiplication, or division
Vocabulary
• Equation
– A mathematical statement that two
expressions are equal
• Solution of an Equation
– Value of the variable that makes the
statement true
Finding Solutions
• In order to find solutions we must,
Isolate the Variable
• A variable is ISOLATED if it appears
by itself on one side of the equation and
not at all on the other side of the
equation
Solving Expressions
• In order to solve any mathematical
expression we must always follow the
order of operations
• PEMDAS
•
•
•
•
•
•
P – Please
E – Excuse
M – My
D – Dear
A – Aunt
S – Sally
Parentheses
Exponents
Multiply
Divide
Add
Subtract
Solving Variable Equations
• In order to Isolate the variable, we
sometimes need to move terms in the
equations
• REMEMBER
– When combining terms on the same side of
the EQUAL SIGN, you keep the SAME sign
of the terms and just add them together
4 x  5  2 y  1  x  3 y 
– We only use the OPPOSITE sign when we
have to cross the equal sign
– This is because we are taking it off one side
and adding it to the other
Angles 4 and 5 are called ?
25%
25%
rP
ai
In
te
r io
r
r
25%
at
e
ne
a
Al
te
rn
Li
A. Vertical
B. Corresponding
C. Linear Pair
D. Alternate Interior
25%
g
7 8
di
n
6
re
sp
on
5
Co
r
3 4
2
Ve
rt
ica
l
1
Angles 1 and 7 are?
1
3 4
5
2
6
7 8
Co
m
pl
en
ta
r
m
im
en
ta
gr
ue
nt
Co
n
0%
y
0%
ry
0%
Su
pp
le
A. Congruent
B. Complimentary
C. Supplementary
Moving Terms
• First look at the problem and decide
which operations you have and do you
have to move them across an equal
sign
• If you do we must do the
Inverse Operation in reverse order of
the Order of Operations
Inverse Operations
Operation
Inverse Operation
Addition
Subtraction
Subtraction
Addition
Multiplication
Division
Division
Multiplication
Examples
x  10  4
2
1
 m
5
5
Examples
x7 9
8  b  2
When multiplying and dividing
• Rules
(+)(+) = (+)
(+)(-) = (-)
  

    
  
  

    
  
  

    
  
  

    
  
Examples
k
4 
5
m
 1.5
3
Examples
7 x  56
5
v  35
9
Homework
• Pg. 80, 21 – 47 EEO
• Pg. 87, 21 – 35 EEO
• EEO
(every other odd)