This includes terms such as 9m, -9m, and 7m.

The terms you've provided, 9m, -9m, and 7m, involve a variable 'm' with different coefficients. - The term 9m means that 'm' is multiplied by 9. - The term -9m indicates that 'm' is multiplied by -9, which is the negative or opposite of 9m. - The term 7m signifies that 'm' is multiplied by 7.

These are considered like terms because they all contain the same variable 'm' raised to the same power (which is 1 in this case, even though it's not explicitly written). Like terms can be combined through addition or subtraction.

For example, if you were to add 9m and 7m, you would combine the coefficients (9 and 7) to get 16m. If you were to subtract -9m from 9m, you would actually be adding the opposite of -9m, which is 9m, resulting in 9m + 9m = 18m, because subtracting a negative is the same as adding a positive.

Extra: It's essential to understand the concept of variables and coefficients when learning algebra.

- A variable is a symbol (commonly a letter) that stands in for an unknown number in mathematical expressions and equations. In the terms 9m, -9m, and 7m, 'm' is the variable. - A coefficient is a number that multiplies the variable. In 9m, the coefficient is 9. In -9m, the coefficient is -9, and in 7m, the coefficient is 7.

Like terms are terms that have exactly the same variables raised to the same powers. You can only perform addition and subtraction on like terms. For example, 9m and 7m can be added to or subtracted from each other because they are like terms. However, if you had a term with different variables or powers, such as 9m² or 9n, you cannot combine these with 9m, -9m, or 7m through addition or subtraction because they are not like terms.

Understanding how to identify and combine like terms is crucial for simplifying algebraic expressions and solving equations. It helps in reducing complex expressions to simpler forms and is one of the fundamental techniques used in algebra.