Transcript solve equations: combine like terms

10-2 Solving Multistep Equations
Warm Up
Solve.
1. (9) - (-7)
16
2. -8 + (-2)
-10
3. -3 - (-6)
3
4. 6 + (-2)
4
Course 3
10-2 Solving Multistep Equations
Continue Learning to solve multi-step
equations.
Course 3
10-2 Solving Multistep Equations
To solve a complicated equation,
you may have to simplify the
equation first by combining like
terms.
Course 3
10-2 Solving Multistep Equations
Additional Example 1: Solving Equations That
Contain Like Terms
Solve.
8x + 6 + 3x – 2 = 37
11x + 4 = 37 Combine like terms.
– 4 – 4 Subtract to undo addition.
11x
= 33
11x = 33 Divide to undo multiplication.
11 11
x=3
Course 3
10-2 Solving Multistep Equations
Try This: Example 1
Solve.
9x + 5 + 4x – 2 = 42
13x + 3 = 42 Combine like terms.
– 3 – 3 Subtract to undo addition.
13x
= 39
13x = 39 Divide to undo multiplication.
13 13
x=3
Course 3
10-2 Solving Multistep Equations
Try This: Example 2
Solve.
36 - 4c – 3c = 22
-7c + 36 = 22 Combine like terms.
–36 –36 Subtract to undo addition.
-7c
= -14
-7c = -14 Divide to undo multiplication.
-7
-7
c=2
Course 3
10-2 Solving Multistep Equations
h + 2h – 26 – 54 = 46
3h – 80 = 46
+ 80 +80
3h
Course 3
= 126
3h 126
3= 3
h = 42
Combine like terms.
Add 80 to both sides.
Divide both sides by 3.
10-2 Solving Multistep Equations
Try This: Example 3
When Mr. and Mrs. Wesner left for the store,
Mrs. Wesner had three times as much money
as Mr. Wesner had. While shopping, Mr.
Wesner spent $50 and Mrs. Wesner spent $25.
When they arrived home, they had a total of
$25. How much did Mr. Wesner have when he
left home?
Let h represent the amount of money that Mr.
Wesner had when he left home. So Mrs. Wesner had
3h when she left home.
Mr. Wesner $ + Mrs. Wesner $
h + 3h – 50 – 25 = 25 – Mr. Wesner spent – Mrs.
Wesner spent = amount left
Course 3
10-2 Solving Multistep Equations
Try This: Example 3 Continued
4h – 75 = 25
+ 75 +75
4h
= 100
4h 100
4= 4
h = 25
Combine like terms.
Add 75 to both sides.
Divide both sides by 4.
Mr. Wesner had $25 when he left home.
Course 3
10-2 Solving
Insert Lesson
Multistep
Title
Equations
Here
Lesson Quiz
Solve.
1. 6x + 3x – x + 9 = 33 x = 3
2. –9 = 5x + 21 + 3x
3. 5 + x = 33
8
8
8
4. 6x – 2x = 25
7
21
21
x = –3.75
x = 28
9
x = 116
5. Linda is paid double her normal hourly rate for each
hour she works over 40 hours in a week. Last week
she worked 52 hours and earned $544. What is her
hourly rate? $8.50
Course 3