1. A = lw 9-8 Transforming Formulas P = 2l + 2w I = Prt D =
A formula is a rule that shows the relationship between two or more quantities
Ex.
Perimeter:
P = 2l + 2w
Interest:
I = Prt
A = lw
Area:
Density:
D =
Distance:
d = rt

2. Solving for a variable is just like solving an equation
Solving for a variable is just like solving an equation. Solve the 
equation below.
4 = 2x
Solve for the variable in red
1). A = lw
2.) y = 3x
3.) I = Prt

3. z c b y a = x = Solve the equation below. 2.) 1.)
Solve for the variable in red
a = b c
x = y z
2.)
1.)

4. 8 = r - 2 1.) t = s - u 2.) x = y - 5 Solve the equation below.
Solve for the variable in red
1.) t = s - u
2.) x = y - 5

5. 18 = 2r + 10 1.) p = 3q - 9 2.) x = 2y + 7 Solve the equation below.
Solve for the variable in red
1.) p = 3q - 9
2.) x = 2y + 7

6. a = x = b + c y + 5 2 3 Solve the equation below. 1.) 2.)
Solve for the variable in red
a =
b + c 3
1.)
2.)
x =
y + 5 2

7. Application:
1. a.)The formula for finding the average of your 3 test grades 
is m = (a + b + c)/3, where a, b, and c are your test grades 
and m is the average (or mean). Solve the formula for c.
 b.) You already took 2 tests and you scored 92% and 
84%. You want to have an A in the class, so what would you 
have to score to have a 90% in the class?

8. Solve the equations for the indicated variable.
1. x = yz for y 2. t = (u + v) for u 
3. p = 3r - 5 for r 4. q = p for p 
5. P = 4s for s 6. y = x + 3 for x 2 r
7 y = 4x for x 8. y = 3x + 2 for x