Question

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

Answer 1

`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`