1. 1.4: Rewrite Formulas & Equations
Objectives:
To solve a formula or equation for a particular variable

2. Formulas!

3. Exercise 1
Given any of the previous formulas, what would it mean to solve for a particular variable? To solve for a variable in an equation or formula means to isolate that variable on only one side of the equation: variable = everything else

4. Exercise 2
Solve C = 2r for r. Then find the radius of a circle with a circumference of 44 in.
Solve V = (4/3)r3 for r. Then find the radius of a sphere with a volume of 36 cm3.

5. Exercise 3
Sometimes the variable you are solving for is part of an expression.
Solve P = 2l + 2w for l. Then find the length of the rectangle whose perimeter is 30 in. and whose width is 7 in.
Solve A = (1/2)(b1 + b2)h for b1.

6. Exercise 4
Write a formula for the area of a circle in terms of its circumference. Then find the area of a circle with a circumference of 12.5 cm.

7. Exercise 5
The equation 3x + 2y = 5 is in standard form. Rewrite the equation in slope-intercept (y = mx + b) form.

8. Exercise 6
What does it mean to solve an equation for y? Solve 2xy – 5y = 8 for y. Then find the value of y when x = 3.

9. Exercise 7 Solve the equation for y. 5y – x = 13 3x + 2y = 12
3 = 2xy – x
4y – xy = 28
2xy + 3yz – 5xz = 12xyz

10. Assignment
P : 3-5, 6-10, 17, 18,21,22, 33,35