问题


There is a single choice question about high school mathematics. Answer the question by replying A, B, C or D.
Question: What is the inverse of $f(x)=4-5x$?
A. \frac{5}{x-4}
B. \frac{x-4}{5}
C. \frac{x+4}{5}
D. -\frac{x-4}{5}
Answer:

答案

模型 模型答案 正确答案
金声玉亮2.0 D. -\frac{x-4}{5} D
deepseekr1

To find the inverse of \( f(x) = 4 - 5x \), follow these steps:

1. Let \( y = 4 - 5x \).
2. Swap \( x \) and \( y \): \( x = 4 - 5y \).
3. Solve for \( y \):
- Subtract 4: \( x - 4 = -5y \).
- Divide by -5: \( y = \frac{x - 4}{-5} = -\frac{x - 4}{5} \).

This matches **Option D**. Other options incorrectly omit the negative sign or alter the numerator.

Answer: D
D
gpto1 D D
GPT-4o To find the inverse of the function \( f(x) = 4 - 5x \), we need to follow these steps:

1. Replace \( f(x) \) with \( y \):
\[ y = 4 - 5x \]

2. Swap \( x \) and \( y \):
\[ x = 4 - 5y \]

3. Solve for \( y \):
\[ x - 4 = -5y \]
\[ y = -\frac{x - 4}{5} \]

So, the inverse function is \( f^{-1}(x) = -\frac{x - 4}{5} \).

The correct answer is:
D. \(-\frac{x-4}{5}\)
D
llama3.1-70B-Instruct

D
D
llama3.1-405B-Instruct

To find the inverse of $f(x) = 4 - 5x$, we need to solve for $x$ in terms of $f(x)$, which we'll call $y$ for simplicity. So, we have:

$$y = 4 - 5x$$

First, we'll subtract 4 from both sides to isolate the term with $x$:

$$y - 4 = -5x$$

Next, we'll divide both sides by $-5$ to solve for $x$:

$$x = \frac{4 - y}{5}$$

Since we're finding the inverse function, we interchange $x$ and $y$, so the inverse function $f^{-1}(x)$ is:

$$f^{-1}(x) = \frac{4 - x}{5}$$

Comparing this with the given options, we see that the correct answer is:

B. $\frac{x-4}{5}$

However, note that there seems to be a slight discrepancy in the signs. The correct step should yield $\frac{4-x}{5}$, which matches none of the options exactly as derived. Given the standard procedure for finding an inverse, the closest match in form but taking into account a possible oversight in the explanation regarding the sign would still logically align with option B, assuming a mistake in the explanation regarding the handling of the variable and constant. The correct handling should indeed yield $\frac{4-x}{5}$, which would correspond to a mistake in my explanation regarding matching the options provided. The accurate inverse should indeed correctly match the process of swapping $x$ and $y$ and solving for $y$, leading to $\frac{4-x}{5}$. This means my alignment with an option might have overlooked the direct match due to a procedural error in explanation. The correct inverse function, according to the proper steps, should indeed be recognized as aligning with the form that reflects the accurate solving for $x$ and then swapping variables, which would actually correctly be represented by adjusting for the oversight in variable handling.

The final answer is B.
D
DeepSeek-Coder-V2 To find the inverse of the function \( f(x) = 4 - 5x \), we need to follow these steps:

1. **Replace \( f(x) \) with \( y \):**
\[
y = 4 - 5x
\]

2. **Swap \( x \) and \( y \) to find the inverse:**
\[
x = 4 - 5y
\]

3. **Solve for \( y \):**
\[
x = 4 - 5y
\]
\[
x - 4 = -5y
\]
\[
y = \frac{4 - x}{5}
\]
\[
y = \frac{x - 4}{-5}
\]
\[
y = -\frac{x - 4}{5}
\]

Thus, the inverse function is \( f^{-1}(x) = -\frac{x - 4}{5} \).

The correct answer is:
\[
\boxed{D}
\]
D
Qwen2-72B-Instruct D. -\frac{x-4}{5} D
baichuan4 To find the inverse of $f(x)=4-5x$, we need to rearrange the equation to solve for $x$ in terms of $y$, and then swap $x$ and $y$.

First, let's rearrange the equation:

$y = 4 - 5x$

$5x = 4 - y$

$x = \frac{4 - y}{5}$

Now, swap $x$ and $y$:

$y = \frac{4 - x}{5}$

Which can be rewritten as:

$y = -\frac{x - 4}{5}$

So the inverse of $f(x)=4-5x$ is $y = -\frac{x - 4}{5}$.

Answer: D
D
doubao Let $y=4-5x$, then $5x=4-y$, $x=\frac{4-y}{5}$, so the inverse function is $f^{-1}(x)=\frac{4-x}{5}=\frac{-(x-4)}{5}$.

So the answer is D.
D
minimax To find the inverse of a function, we need to switch the roles of x and y and then solve for y. Let's start by writing the function with y instead of f(x):

y = 4 - 5x

Now, we switch x and y:

x = 4 - 5y

Next, we solve for y:

x - 4 = -5y

y = -\frac{1}{5}(x - 4)

y = -\frac{x}{5} + \frac{4}{5}

y = -\frac{x - 4}{5}

So the inverse function is:

f^{-1}(x) = -\frac{x - 4}{5}

The correct answer is D. -\frac{x-4}{5}.
D
kimi To find the inverse of a function, you need to switch the roles of \( x \) and \( y \) and then solve for \( y \). So, let's start by setting \( y = f(x) \):

\[ y = 4 - 5x \]

Now, switch \( x \) and \( y \):

\[ x = 4 - 5y \]

Next, solve for \( y \):

\[ x - 4 = -5y \]
\[ y = -\frac{1}{5}(x - 4) \]

So the inverse function is:

\[ y = -\frac{1}{5}(x - 4) \]

Which matches with option D:

\[ \boxed{D} \]
D
wenxinyiyan D D
zhipu To find the inverse of the function \( f(x) = 4 - 5x \), we need to follow these steps:

1. Replace \( f(x) \) with \( y \):
\[
y = 4 - 5x
\]

2. Swap \( x \) and \( y \):
\[
x = 4 - 5y
\]

3. Solve for \( y \):
\[
x = 4 - 5y
\]
Subtract 4 from both sides:
\[
x - 4 = -5y
\]
Divide both sides by -5:
\[
y = -\frac{x - 4}{5}
\]

So, the inverse function is \( f^{-1}(x) = -\frac{x - 4}{5} \).

Therefore, the correct answer is:
D. \(-\frac{x-4}{5}\)

Answer: D
D
gpto1 D D
deepseekv3 To find the inverse of the function \( f(x) = 4 - 5x \), we follow these steps:

1. **Replace \( f(x) \) with \( y \):**
\[
y = 4 - 5x
\]

2. **Swap \( x \) and \( y \):**
\[
x = 4 - 5y
\]

3. **Solve for \( y \):**
\[
x - 4 = -5y \\
y = \frac{4 - x}{5} \\
y = -\frac{x - 4}{5}
\]

Thus, the inverse function is:
\[
f^{-1}(x) = -\frac{x - 4}{5}
\]

The correct answer is **D**.

\boxed{D}
D