1. Rewrite Equations and Formulas Lesson 3.8 OBJ: To recognize and solve literal equations; to rewrite equations and formulas.

2. Literal Equation An equation with two or more variables. An equation in which letters are used to replace coefficients and constants of another equation. Examples:

3. Solving Literal Equations Solving equations for one variable in terms of the other variables without substituting any values. Examples: Solve V =lwh for h. Solve A = p +prt for r. Solve A = p + prt for p. **Use the same rules for solving equations. The only difference is that it is not numbers, it is only variables.

4. Solve literal equations Solve ax + b = c for x. Then use the solution to solve 2x + 5 = 11 Step 1: Solve ax + b = c for x Step 2: Use the solution to solve 2x + 5 = 11. The solution of 2x + 5 = 11 is 3. Example: Solve p + qx = r for x. Then use the solution to solve 3+5x = -7.

5. Two or more variables… Write -2x + 3y = 6 so that y is a function of x. This means solve for y. Write 12 = 9x + 3y so that y is a function of x. Write 14 = 7y – 6x so that y is a function of x.

6. Solve and use Geometric Formulas The area for a rectangle is given by the formulas A = lw, where l is the length and w is the width. Solve the formula for the length l. Use the rewritten formula to find the length of this rectangle. A = 351 cm 2 13 cm

7. Homework Text p. 187- 188 #’s 3-6, 12 – 18 evens, 20 -22, 24, 26, 27, 32, 33