1. Math Humor
Customer: How much are two eggs? Waitress: $1.75 Customer: How much is one egg? Waitress: $1.50 Customer: Then I’ll have the other one.

2. Use properties of equality and congruence to write Algebraic proofs.
LT 2.5:
Use properties of equality
and congruence to write
Algebraic proofs.

4. Today we are going to prove that 1=2 as we learn how to write an Algebraic proof. Hopefully you know that 1≠2 which means there is a logical mistake. See if you can figure out what the mistake is.

5. Justifications in an Algebraic Proof.
What we write: What is means:

6. Solve each equation. Write a justification for each step.
Statements Reasons
y + 1 = 5

7. Solve each equation. Write a justification for each step.
Statements Reasons

8. Solve each equation. Write a justification for each step.
Statements Reasons 0 = 2(r – 3) + 4

9. Write a justification for each step.
Statements Reasons

10. Given that a=b, prove 1=2
Statements
Reasons
a=b
b=a
ab = a2
ab - b2 = a2 - b2
b(a-b) = (a+b)(a-b)
b=a+b
b = 2b
1=2
Can YOU figure out what is wrong with this proof???

12. Identify the property that justifies each statement.
9) 10) 11) 12)

13. Statements Reasons

14. Before you leave… A B C