Download 1. Undo Addition or Subtraction. 2. Undo Multiplication or Division.

7-1
Pre-Algebra
Solving Two-Step Equations
Objectives: 1.
2.
OBJECTIVE
1
Using Properties to Solve Two-Step Equations
IMPORTANT !!!
Solving Two-Step Equations
1. Undo Addition or Subtraction.
2. Undo Multiplication or Division.
EXAMPLE 1
Undoing an Operation
Solve each equation.
1. 3n – 6 = 15
STEPS
1. Undo subtraction by adding 6 to each side.
2. Simplify.
3. Undo multiplication by dividing each side by 3.
4. Simplify.
5. Check.
2. 15x + 3 = 48
3.
t
4
- 10 = -6
4.
b
+ 13 = 11
3
5. 9g + 11 = 2
6. 5v – 12 = 8
8. 3x – 5 = 10
9.
EXAMPLE 2
n
+ 10 = 7
2
7. 3x + 4 = 10
10.
m
- 9 = -5
7
Negative Coefficients
Solve each equation.
1. 5 – x = 17
STEPS
1. Subtract 5 from each side.
2. Simplify.
3. 0 – x = -x
4. Divide each side by -1.
5. Simplify.
2. -a + 6 = 8
3.
-9 –
y
= -12
7
4. 13 – 6f = 31
OBJECTIVE
2
EXAMPLE 3
Solving Problems with Two-Step Equations
Real-World Problem Solving
1. Lynne wants to save $99 to go to Puerto Rico. She saves
$45 each week and now has $180. To find how many more
weeks w it will take to have $900, solve 180 + 45w = 900.
2. Jacob bought four begonias in 6-in. pots and a $19 fern at a fundraiser. He spent a total of
$63. Solve the equation 4p + 19 = 63 to find the price p of each begonia.
3. You borrow $350 to buy a bicycle. You agree to pay $100 the first week, and then $25 each
week until the balance is paid off. To find how many weeks w it will take you to pay for the bike,
solve 100 + 25w = 350.
Pre-Algebra Objectives 7.1
The student should be able….
1. To solve two-step equations.
2. To use two-step equations to solve problems.