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Geometry Notes
Sections 2-6
Solve the following equation:
m – 17 = 8
Solve the following equation:
y
 12  14
6
Solve the following equation:
-6x + 33 = 0
Solve the following equation:
3(x - 2) = 42
What you should learn
How to use algebra to write two-column
proofs
 How to use properties of equality in
geometry proofs

Vocabulary
Deductive argument
 Two-column proof
 Formal poof

Properties of Equality for Real Numbers
You can add/subtract the same
Addition/Subtraction
Properties of Equality value from both sides of an
equation
You can multiply/divide both
Multiplication/Division
sides of an equation by the
Properties of Equality
same value
Substitution
Property of Equality
You can replace one thing with
another of EQUAL value
a(b + c) = ab + ac AND
Distributive Property
ab + ac = a(b + c)
Properties of Equality for Real Numbers
Reflexive Property
of Equality
Symmetric Property
of Equality
Transitive Property
of Equality
A number is equal to itself.
a=a
You can switch the left and
right sides of an equation
If a = b then b = a
If a = b and b = c
then a = c
Have you learned .. . .
How to use algebra to write two-column
proofs?
 How to use properties of equality in
geometry proofs?
 Assignment: Worksheet 2.6
