1. HMWK: p. 100, #s 17 – 23 odd, 24 – 28 all Game Plan: Warm-up:
Today I will be able to use Algebraic properties to reason.
Warm-up:
Solve each equation. SHOW ALL STEPS.
3x = 27
x+6 = -17
x – 9 = 18
(2/3)x = 6
x = 9
x = -23
x = 27

2. Algebraic Properties Let a, b, and c be real numbers.
Addition Property:
If a = b, then a + c = b + c
ex: a = 3, b = 3, c = 5
a = b, then a + c = b + c
3 = 3, = 3 + 5

3. Algebraic Properties Subtraction Property:
If a = b, then a – c = b – c
Ex:

4. Algebraic Properties Multiplication Property: If a = b, then ac = bc
Ex: a = 11, b = 11, c = 8
a = b, then ac = bc
11 = 11, 11(8) = 11(8)

5. Algebraic Properties Division Property:
If a = b and c  0, then a/c = b/c.
Ex:

6. Examples Solve 3x + 12 = 8x – 18 and write a reason for each step.
2. A child’s dose (c) for a medicine with an adult dose of 500mg can be found by using the child’s age (a) in years in the given formula. Solve the formula for c and write a reason for each step.

7. R,S,T Properties of Algebra
Reflexive: For any real number a, a = a.
Symmetric: If a = b, then b = a.
Transitive: If a = b and b = c, then a = c.
Substitution: If a = b, then a may be substituted for b in any equation or expression.

8. R,S,T Properties of Equality
Property
Segments
Angles
Reflexive
For any segment AB, AB = AB
For any angle A, mA = mA.
Symmetric
If AB=CD, then CD=AB
If mA = mB, then mB = mA
Transitive
IF AB=CD and CD=EF, then AB=EF.
If the mA = mB and mB = mC, then mA = mC.

9. Examples
Worksheet

10. Wrap-up What properties do R, S, and T stand for?
If AB = CD, and CD = EF, write a valid statement about AB and EF and give a reason.