1. 2-5 Algebraic Proof
Geometry

2. Properties of Equality
For all properties, a, b, & c are real #s.
Addition property of equality- if a=b, then a+c=b+c. (can add the same #, c, to both sides of an equation)
Subtraction property of equality - If a=b, then a-c=b-c. (can subtract the same #, c, from both sides of an equation)
Multiplication prop. of equality- if a=b, then ac=bc.
Division prop. of equality- if a=b, then

3. Properties of = (cont.) Reflexive prop. of equality- a=a
Symmetric prop of equality- if a=b, then b=a.
Transitive prop of equality- if a=b and b=c, then a=c.
Substitution prop of equality- if a=b, then a can be plugged in for b and vice versa.
Distributive prop.- a(b+c)=ab+ac OR
(b+c)a=ba+ca

4. Ex 1: Solve the equation & write a reason for each step.
2(3x+1)=5x+14
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5. Ex. 2)Solve 55z - 3(9z + 12) = - 64 & write a reason for each step.
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6. Ex. 3 Solving an Equation in Geometry
Write a justification for each step
4x-4
N 2x M 3x O
NO = NM + MO _______________
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7. Properties of Congruence
Reflexive Prop. Of Congruence
Symmetric Prop. Of Congruence
Transitive Prop. Of Congruence

8. Ex. 4 Identify the property that justifies each statement.
b.)
c.)
d.)

9. Assignment