1. Essential Question: What does it mean to say two quantities are equal?
Solving Equations
Essential Question: What does it mean to say two quantities are equal?

2. Real World Example
An angelfish can grow to be 12 inches long. If an angelfish is 8.5 inches longer than a clown fish, how
long is a clown fish?

3. Check it out!
An angelfish is 8.5 inches longer than a clown fish
Let c represent the length of the clown fish
= c
= c
The clown fish is 3.5 inches long

4. Subtraction Property of Equality
The subtraction Property of Equality states that the two sides of an equation remain equal when you subtract the same number from each side.
If a = b, then a – c = b – c.

5. Got it? Do this problem to find out.
The highest recorded temperature in Warsaw, Missouri, is 118°F. This is 158° greater than the lowest recorded temperature. Find the lowest recorded temperature.

7. Another example A pair of shoes costs $25. This is $14
less than the cost of a pair of jeans.
Find the cost of the jeans.
Let j represent the cost of jeans.

8. Addition Property of Equality
The Addition Property of Equality states that the two sides of an equation remain equal when you add the same number to each side.
If a = b, then a + b = a + c

9. Real World Example Jessica sent 574 text messages last week.
On average, how many messages did she
send each day?

10. Check it out! Let m represent the number of messages Jessica sent.
82 = m
Jessica sent 82 messages on average each day.

11. Try another… The distance d Diana travels in her car
While driving 60 miles per hour for 3 hours
is given by the equation How far
did she travel?

12. Check it out!
Diana traveled 180 miles.