What type of terms does the expression 9x - 4x consist of?

The expression 9x - 4x consists of like terms because they both contain the same variable, x, raised to the same power (which is 1 in this case). When terms share the same variable and exponent, they can be combined through addition or subtraction, which is what occurs in this expression.

In the context of this expression, both terms represent quantities that are associated with the variable x, allowing you to simplify the expression by combining them. Therefore, when combining them, you would subtract the coefficients (9 and 4), leading to 5x.

Recognizing like terms is crucial in algebra because this understanding allows for the simplification of expressions and the solving of equations effectively.