Final answer:
To determine the value of 7.5(3x + 4) when x = 7, you substitute 7 into the expression, calculate 3(7) + 4 to get 25, and then multiply 7.5 by 25 to obtain the final answer of 187.5.
Step-by-step explanation:
The student asked what the value of 7.5(3x + 4) is, when x = 7. To solve this, we'll follow these steps:
- Substitute x with 7 in the expression 3x + 4, which gives us 3(7) + 4.
- Perform the multiplication: 3 times 7 equals 21.
- Add 4 to 21, resulting in 25.
- Now multiply 7.5 by 25 to get the final answer.
- 7.5 times 25 equals 187.5.
Hence, the value of 7.5(3x + 4) when x = 7 is 187.5.