Unit 1:
Algebraic Operations
Chapter 2: Linear Equations and Formulae
Solving Equations
1.2.3 Solve a linear equation with
multiple unknowns for any variable
• Given a linear equation with more than one
unknown, solve for the indicated variable
Workbook p. 71 - 73
Solving Equations
for Variables
Example:
Here we must get alone on one side of the
equation.
 Some equations have more than one variable. We
can solve an equation for one variable by
rearranging the equation to get the variable alone
on one side of the equation.
Solve 3 10 forx y x
x
To solve for a variable, follow these
steps:
Write the equation
Move the variable you are solving for to the left
side of the equation
Move all other variables and numbers to the
right side of the equation using the properties of
equality.
Solving Equations
for Variables
Solving Equations
for Variables
Solve 3 10 forx y x
3 10x y
3 10x y
3 10
1 1
3 3
x y
1
3
10
3
y
x
Example:
Write the equation: x is already
on the left side of the equation
Move y to the right side and change
its sign.
We need x alone, so multiply by to
remove the 3.
This is the answer, because x is
alone on one side of the equation 
Solving Equations
for Variables
1
2
Example:
Write the equation: is already
on the left side of the equation
Move to the right side and change
its sign.
We need alone, so multiply by to
remove the 2.
This is the answer, because is
alone on one side of the equation 
Solve 2 3 21 fora b a
2 3 21a b a
2 1 32a b 3b
2 21 3
1 1
2 2
a b a
21 3
2
b
a a
Solving Equations
for Variables
5
Example:
Write the equation: is already
on the left side of the equation
Move to the right side and change
its sign.
We need alone, so multiply by to
remove the .
This is the answer, because is
alone on one side of the equation 
m
2
m
m
1
Solve 2 6 for
5
m n m
1
2 6
5
m n
1
6
5
2m n
5 5
1
2 2
5
m n
10 10m n
1
5
Solving Equations
for Variables
1
Example:
Write the equation: is already
on the left side of the equation
Move to the right side and change
its sign.
We need alone, so multiply by to
remove the negative.
This is the answer, because is
alone on one side of the equation 
b
3x
b
b
Solve 3 forx b m b
3x b m
3xb m
( ) (( 3) ( ))1 1b m x
3 or
3
b m x
b x m
Solving for Variables
Checkpoint p. 72
Solve the equation 6 8 15 for pp q
Workbook p. 72 – 73
Solving for Variables

1.2.3 solving linear equations (multiple unknowns)

  • 1.
    Unit 1: Algebraic Operations Chapter2: Linear Equations and Formulae
  • 2.
    Solving Equations 1.2.3 Solvea linear equation with multiple unknowns for any variable • Given a linear equation with more than one unknown, solve for the indicated variable Workbook p. 71 - 73
  • 3.
    Solving Equations for Variables Example: Herewe must get alone on one side of the equation.  Some equations have more than one variable. We can solve an equation for one variable by rearranging the equation to get the variable alone on one side of the equation. Solve 3 10 forx y x x
  • 4.
    To solve fora variable, follow these steps: Write the equation Move the variable you are solving for to the left side of the equation Move all other variables and numbers to the right side of the equation using the properties of equality. Solving Equations for Variables
  • 5.
    Solving Equations for Variables Solve3 10 forx y x 3 10x y 3 10x y 3 10 1 1 3 3 x y 1 3 10 3 y x Example: Write the equation: x is already on the left side of the equation Move y to the right side and change its sign. We need x alone, so multiply by to remove the 3. This is the answer, because x is alone on one side of the equation 
  • 6.
    Solving Equations for Variables 1 2 Example: Writethe equation: is already on the left side of the equation Move to the right side and change its sign. We need alone, so multiply by to remove the 2. This is the answer, because is alone on one side of the equation  Solve 2 3 21 fora b a 2 3 21a b a 2 1 32a b 3b 2 21 3 1 1 2 2 a b a 21 3 2 b a a
  • 7.
    Solving Equations for Variables 5 Example: Writethe equation: is already on the left side of the equation Move to the right side and change its sign. We need alone, so multiply by to remove the . This is the answer, because is alone on one side of the equation  m 2 m m 1 Solve 2 6 for 5 m n m 1 2 6 5 m n 1 6 5 2m n 5 5 1 2 2 5 m n 10 10m n 1 5
  • 8.
    Solving Equations for Variables 1 Example: Writethe equation: is already on the left side of the equation Move to the right side and change its sign. We need alone, so multiply by to remove the negative. This is the answer, because is alone on one side of the equation  b 3x b b Solve 3 forx b m b 3x b m 3xb m ( ) (( 3) ( ))1 1b m x 3 or 3 b m x b x m
  • 9.
    Solving for Variables Checkpointp. 72 Solve the equation 6 8 15 for pp q
  • 10.
    Workbook p. 72– 73 Solving for Variables