Mrs Volynskaya LITERAL EQUATIONS A formula is a

Mrs. Volynskaya LITERAL EQUATIONS A formula is a type of literal equation. A literal equation is an equation with two or more variables. To solve for one of the variables, use inverse operations.

Solving for a Variable Step 1 Locate the variable you are asked to solve for in the equation. Step 2 Identify the operations on this variable and the order in which they are applied. Step 3 Use inverse operations to undo operations and isolate the variable.

x - 4 y = 7 for x 1) Solve 2 x 1. 2. 3. 4. Add 4 y to both sides Simplify Divide both sides by 2 Does it simplify? 2 x - 4 y = 7 + 4 y 2 x = 7 + 4 y 2 2 This fraction cannot be simplified because both terms in the numerator are not divisible by 2.

2) Solve 2 x - 4 y = 7 for y To get y by itself, what is the first step? 1. 2. 3. 4. Add 2 x Subtract 2 x Add 4 y Subtract 4 y Answer Now

y = 7 for y 3) Solve 2 x - 4 y 1. Subtract 2 x from both sides 2. Simplify 3. Divide both sides by -4 4. Does it simplify? 2 x - 4 y = 7 -2 x -4 y = 7 - 2 x -4 -4 Nope!

4) Solve for y: 4 x – 2 y = 12 1. Subtract 4 x from both sides 2. Simplify 3. Divide both sides by -2 4. Does it simplify? Yes! or 4 x – 2 y = 12 - 4 x -2 y = 12 – 4 x -2 -2 y = -6 + 2 x y = 2 x - 6

y = 12 5) Solve for y: 4 x – 2 y 1. 2. 3. 4. -4 x + 12 4 x - 12 -2 x + 6 2 x - 6 Answer Now

9 x – 7 y = -7 1. Solve for x 2. Solve for y

Lesson Quiz: Part I Solve for the indicated variable. 1. for h 2. P = R – C for C C=R–P 3. 2 x + 7 y = 14 for y 4. for m 5. for C m = x(k – 6) C = Rt + S

Lesson Quiz: Part II Euler’s formula, V – E + F = 2, relates the number of vertices V, the number of edges E, and the number of faces F of a polyhedron. 6. Solve Euler’s formula for F. F = 2 – V + E 7. How many faces does a polyhedron with 8 vertices and 12 edges have? 6