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

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

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.)

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

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

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

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?

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