Answer:
- b) 7r +r +2
- d) 3u +1 +7y
Explanation:
Identify the variable in each term. If two or more terms have the same variable, they are "like" terms.*
1) Like terms are found in selection b. They are 7r and r.
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2) The variables in selection d are u and y, not the same. Only unlike terms are found in selection d. (Selection b has variables x, b, x. The x-terms are like terms and can be combined.)
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* Strictly speaking, it is the constellation of variables you want to match. For example, terms 3xy, 4xy², and -5x²y all have variables x and y, but the powers of those variables don't match from term to term. For terms to be "like", the variables and their powers need to match.