5. 2-8 Division Equations
Multiplication is the inverse of division.
When an equation contains division, use
multiplication to “undo” the division.
Course 1
6. 2-8 Division Equations
Additional Example 1A: Solving Division Equations
Solve the equation. Check your answer.
x =5
7
x =5
7 x is divided by 7.
7• x = 7• 5 Multiply both sides by 7 to undo
7 the division.
x = 35
Check
x =5
7
35 = 5
?
Substitute 35 for x in the equation.
7
?
5=5 35 is the solution.
Course 1
7. 2-8 Division Equations
Additional Example 1B: Solving Division Equations
Solve the equation. Check your answer.
13 = p
6
13 = p p is divided by 6.
6
6 • 13 = 6 • p Multiply both sides by 6 to undo
6 the division.
78 = p
Check 13 =
p
6
13 = 78 Substitute 78 for p in the equation.
?
6
?
13 = 13 78 is the solution.
Course 1
8. 2-8 Division Equations
Check It Out: Example 1A
Solve the equation. Check your answer.
x =9
2
x =9 x is divided by 2.
2
2• x = 2• 9 Multiply both sides by 2 to undo
2 the division.
x = 18
Check
x =9
2
18 = 9
?
2 Substitute 18 for x in the equation.
?
9=9 18 is the solution.
Course 1
9. 2-8 Division Equations
Check It Out: Example 1B
Solve the equation. Check your answer.
72 = p
4
72 = p p is divided by 4.
4
4 • 72 = 4 • p Multiply both sides by 4 to undo
4 the division.
288 = p
Check 72 =
p
4
72 = 288 Substitute 288 for p in the equation.
?
4
?
72 = 72 288 is the solution.
Course 1
10. 2-8 Division Equations
Additional Example 2: Application
At Elk Meadows Park an aspen tree is one-
third the height of a pine tree.
height of aspen = height of pine
3
The aspen tree is 14 feet tall. How tall is the
pine tree?
Let h represent the height of the pine tree.
14 = h Substitute 14 for height of
3 aspen. h is divided by 3.
3 • 14 = 3 • h Multiply both sides by 3 to undo
3 the division.
42 = h
The pine tree is 42 feet tall.
Course 1
11. 2-8 Division Equations
Check It Out: Example 2
Jamie weighs one-half as much as her father.
Jamie’s weight = father’s weight
2
Jamie weighs 95 pounds. How many pounds
does her father weigh?
Let w represent her father’s weight.
95 = w Substitute 95 for Jamie’s
2 weight. w is divided by 2.
2 • 95 = 2 • w Multiply both sides by 2 to undo
2
the division.
190 = w
Jamie’s father weighs 190 pounds.
Course 1
12. 2-8 Division Equations
Lesson Quiz
Solve each equation. Check your answers.
1. x = 7 x = 70
10
2. 8 = x x = 32
4
3. x = 11 x = 99
9
4. x = 7 x = 105
15
5. The area of Sherry’s flower garden is one-
fourth the area of her vegetable garden. The
area of the flower garden is 17 square feet. Let x
represent the area of her vegetable garden. Find
the area of her vegetable garden? 68 square feet
Course 1
