Final answer:
The expression 5x - 9 is correctly represented by the phrase 'the difference of five times a number and nine' which corresponds to option D. The term 'five times' indicates multiplication while the 'difference of' signifies subtraction.
Step-by-step explanation:
The phrase that represents the algebraic expression 5x - 9 is D) the difference of five times a number and nine. This expression consists of two parts: the '5x' implies that you have some number, which we represent with the variable 'x', and you're multiplying it by five. Then you subtract nine from the result of that multiplication.
To understand this, let's break it down:
- Multiplication: The term 'five times a number' tells us that we're doing multiplication ('times' is a keyword for multiplication). When two positive numbers multiply, the answer is positive. Example: 2x3 = 6.
- Subtraction: The term 'the difference of' typically signifies subtraction. In subtraction, change the sign of the subtracted number and then follow the addition rules. For example, subtract 3 from 5: 5-(+3) = 5-3 = 2.
The other choices do not correctly describe the expression:
- A) This would be '5x + 9' which is not our expression.
- B) This could represent '9x - 5' which is also not our expression.
- C) Implies an addition, '5x + 5', which is incorrect.