Are 1 and 18 like numbers?

Answer 1

Like terms are terms that have the same variables and exponents. Some examples:

1. -7x² and 5x² are like terms since they have the same variable (x) to the same power (2)
2. 2xy and 3xy are like terms - same variables (x and y) to the same power (1)
3. 1 and 18 are like terms since they have the same variables (none) to the same power (none)

2x²y and 2xy² are NOT like terms. They have the same variables but different powers (x vs. x² and y vs. y²). You can add like terms, so -7x² + 5x² = -2x². You cannot add unlike terms.

Answer 2

Do you mean like terms? If so, yes.