Pre-Algebra Demystified

Math Note: An algebraic expression of the form aþ(
b) is usually

written as a
b.

PRACTICE

For each of the following expressions, combine like terms:

1. 10xþ21x


2. 18y
   12y


3. x
   6x


4. 3xþ5xþ6x
   2x


5. 
   4y
   7y
   11y


6. 25x
   2yþ13x
   6yþx


7. 4xþ2y
   6 þ3x
   5yþ 2


8. 7a
   6bþ3c
   4a
   2bþ5c


9. xþ2y
   x
   yþ5x


10. 8pþq
    6p
    q

ANSWERS

1. 31x


2. 6y


3. 
   5x


4. 12x


5. 
   22y


6. 39x
   8y


7. 7x
   3y
   4


8. 3a
   8bþ8c


9. 5xþy


10. 2p

Removing Parentheses and Combining

Like Terms

Sometimes in algebra it is necessary to use the distributive property to

remove parentheses and then combine terms. This procedure is also called

‘‘simplifying’’ an algebraic expression.

132 CHAPTER 7 Expression and Equations