1. 2-2 Properties from Algebra
Notes on worksheet

2. Properties from Algebra
See Worksheet!
Addition Property
Subtraction Property
Multiplication Property
Division Property
You can +/-/x/÷ the same number on both sides of an equation

3. Properties from Algebra
Substitution: think “replace”
Ex: a+b=c, if c = 8 then a + b = 8
Questions on Substitution???
We use this ALOT in Proofs!
Reflexive: a # equals itself (same on both side)
Symmetric: switch the side of the equal sign it is on
Transitive (3 parts)
Ex: = • 2 = 10
6 + 4 = 5 • 2

4. Properties from Algebra
Properties of Congruence: Properties of Equality where the equal sign is replaced with a congruency sign.
Distributive Property
If a(b + c), then ab + ac
What do you notice about all the properties?
They are If-Then statements!

5. Example Justify the statement: If WX = YZ, then WY = XZ
addition: we added the segment
XY to both sides of the
original equation W X Y Z

6. Example Justify the statement: If WY = XZ, then WX = YZ
subtraction: we subtracted the
segment XY from both
sides of the original
equation W X Y Z

7. TOO—on Whiteboards!!!! If 4x = -24, then x = -6 DIVISION!
If a = b and b = c then a = c.
Transitive!
Angle A = Angle A
Reflexive!

8. Homework Worksheet 2-1 and 2-2
Skip #14 the Proof, We will do it together tomorrow