How do you combine like terms in #5b - 9+ 2b#?

1 Answer
Oct 23, 2016

#7b-9#

Explanation:

#color(red)(5b)-color(blue)9+color(red)(2b)#

This expression has two types of terms: variable and constant. Variable terms have a "variable" or letter. Constant terms have only a numeral. Only terms of the same type may be "combined", which means added or subtracted.

Variable terms: #color(red)(5b)# and #color(red)(2b)#

Constant term: #color(blue)(9)#

To combine like terms, add the variable terms #color(red)(5b)# and #color(red)(2b)#. Think of this as adding 5 "b"s and 2 "b"s to get 7 "b"s.

The expression then simplifies to #color(red)(7b)-color(blue)9#