1. 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.

2. 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.

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

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

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

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

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

8. 9x – 7y = -7
1. Solve for x
2. Solve for y

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

10. 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