Simplifying Expressions (Combine Like Terms)

ALGEBRA NOTES (7th)

Solving Equations (1-step)

x + 4 = 12 à you do the opposite, so subtract 4 from both sides

-4 -4

x = 8 à your answer is 8

8 + 4 = 12 à check your work by plugging in your answer for x.

x – 5 = 13 à you do the opposite, so add 5 to both sides

+ 5 +5

x = 18 à your answer is 18

18 – 5 = 13à check your work by plugging in your answer for x.

3x = 15 à you do the opposite, so divide both sides by the coefficient (3)

3 3

x = 5 à your answer is 5

3 (5) = 15 à check your work by plugging in your answer for x.

= 6 à you do the opposite, so multiply both sides by 4

x = 24 à your answer is 24

24 = 6 à check your work by plugging in your answer for x.

Solving Equations (2-step)

4x – 9 = -29 à first, add 9 to both sides

+ 9 + 9

4x= -20 àsecond, divide both sides by 4

4x = -20

4 4

x = -5 à your answer is –5

4 (-5) – 9 = -29

-20 –9 = -29 à check your work by plugging in your answer for x.

5x + 8 = 28 à first, subtract 8 from both sides

- 8 -8

5x= 20 àsecond, divide both sides by 5

5x = 20

5 5

x = 4 à your answer is 4

5(4) + 8 = 28

20 + = 28 à check your work by plugging in your answer for x.

+ 12 = 3 à first, subtract 12 from both sides

-12 -12

= -9 àsecond, multiply both sides by 4

x =-36 àyour answer is –36

+ 12 = 3 à check your work by plugging in your answer for x.

-9 + 12 = 3