Answer :
- Substitute $x = 6$ into the function $f(x) = 7x - 4$.
- Calculate $7 \times 6 = 42$.
- Subtract 4 from 42: $42 - 4 = 38$.
- The final answer is $\boxed{38}$.
### Explanation
1. Understanding the problem
We are given the function $f(x) = 7x - 4$, and we want to find the value of $f(6)$. This means we need to substitute $x = 6$ into the expression for $f(x)$.
2. Substitution
Substitute $x = 6$ into the function: $$f(6) = 7(6) - 4$$
3. Multiplication
Now, we perform the multiplication: $$f(6) = 42 - 4$$
4. Subtraction
Finally, we subtract: $$f(6) = 38$$
5. Final Answer
Therefore, $f(6) = 38$. The correct answer is A.
### Examples
In real life, this type of function evaluation can be used to model various scenarios. For example, imagine a taxi service charges a fixed fee of $4 and an additional $7 per mile. The function f(x) = 7x - 4 could represent the total cost of a ride, where x is the number of miles traveled. Evaluating f(6) would tell you the cost of a 6-mile ride. Understanding function evaluation helps in predicting costs, calculating profits, or modeling relationships between different quantities.
- Calculate $7 \times 6 = 42$.
- Subtract 4 from 42: $42 - 4 = 38$.
- The final answer is $\boxed{38}$.
### Explanation
1. Understanding the problem
We are given the function $f(x) = 7x - 4$, and we want to find the value of $f(6)$. This means we need to substitute $x = 6$ into the expression for $f(x)$.
2. Substitution
Substitute $x = 6$ into the function: $$f(6) = 7(6) - 4$$
3. Multiplication
Now, we perform the multiplication: $$f(6) = 42 - 4$$
4. Subtraction
Finally, we subtract: $$f(6) = 38$$
5. Final Answer
Therefore, $f(6) = 38$. The correct answer is A.
### Examples
In real life, this type of function evaluation can be used to model various scenarios. For example, imagine a taxi service charges a fixed fee of $4 and an additional $7 per mile. The function f(x) = 7x - 4 could represent the total cost of a ride, where x is the number of miles traveled. Evaluating f(6) would tell you the cost of a 6-mile ride. Understanding function evaluation helps in predicting costs, calculating profits, or modeling relationships between different quantities.
