Is there a number that is exactly 5 more than its cube?

Let’s explore the equation that describes this problem. We are trying to find a number, say x, such that:

x = x3 + 5

This can be rearranged to:

x3 – x + 5 = 0

Now, the next step is to check if there are any real solutions to this cubic equation. We can begin by testing some small integer values for x.

If we try x = 1:

13 – 1 + 5 = 1 – 1 + 5 = 5 (not a solution)

If we try x = 2:

23 – 2 + 5 = 8 – 2 + 5 = 11 (not a solution)

If we try x = -1:

(-1)3 – (-1) + 5 = -1 + 1 + 5 = 5 (not a solution)

If we try x = -2:

(-2)3 – (-2) + 5 = -8 + 2 + 5 = -1 (not a solution)

We can see that these tests are not yielding a solution. To determine if a solution exists, we could analyze the behavior of the function f(x) = x3 – x + 5. This is a continuous function and we can look at limits as x approaches positive and negative infinity:

As x → ∞, f(x) → ∞

As x → -∞, f(x) → -∞

Since the function is continuous, by the Intermediate Value Theorem, there must be at least one real solution in between these limits. However, finding the exact solution can be complex and might require numerical methods or graphing techniques.

In conclusion, while there is likely a real number that satisfies the condition, it may not be a simple integer or rational number. Further mathematical techniques or numerical approximation methods could pinpoint the exact solution.

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