1. Literal Equations

2. Warm Up In January 2011, the national average for 5 gallons of gas was $17.20. 1. What was the national average for 1 gallon of gas? 2. What was the price for 18 gallons of gas?

3. What is a literal equation? Literal equations are equations that involve two or more variables. Literal equations can be solved for a specific variable for isolating that variable

4. Example 1 Solve 6y – 12x = 18 for the variable y:

5. Example 2 Solve 15x – 5y = 25 for the variable y

6. Example 3 Solve 4y + 3x = 16 for the variable y

7. Example 4 The formula for finding the area of a triangle is A = ½ bh, where b is the length of the base and h is the height of the triangle. Suppose you know the area and the height of the triangle, but need to find the length of the base. In this case, solving the formula for b would be helpful.

8. Example 5 The distance, d, that a train can travel is found by multiplying the rate of speed, r, by the amount of time the train is traveling, t, or d = rt. Solve this formula for t to find the amount of time the train will travel given a specific distance and rate of speed.

9. You Try The formula N = 7LH is used to determine N, the number of bricks needed to build a wall that is L feet in length and H feet high. A customer would like a wall constructed that is 4 feet high. If the bricklayer wants to use all of the 1,820 bricks that he has readily available, how long will the wall be?