At Westonci.ca, we make it easy to get the answers you need from a community of informed and experienced contributors. Our platform connects you with professionals ready to provide precise answers to all your questions in various areas of expertise. Get detailed and accurate answers to your questions from a dedicated community of experts on our Q&A platform.

Does the expression [tex]\(\frac{x^3-1}{x^2-1}\)[/tex] simplify to [tex]\(x\)[/tex]?

A. Yes, because [tex]\(x^3 - 1\)[/tex] can be factored as [tex]\((x-1)(x^2 + x + 1)\)[/tex] and [tex]\(x^2 - 1\)[/tex] can be factored as [tex]\((x-1)(x+1)\)[/tex], so [tex]\((x-1)\)[/tex] can be canceled.

B. No, because the [tex]\(-1\)[/tex] in the numerator and denominator is not a common factor and cannot be canceled.


Sagot :

To determine whether the expression [tex]\(\frac{x^3 - 1}{x^2 - 1}\)[/tex] simplifies to [tex]\(x\)[/tex], let's conduct a step-by-step simplification of the expression.

### Step 1: Factor the Numerator and Denominator
First, we need to factor both the numerator ([tex]\(x^3 - 1\)[/tex]) and the denominator ([tex]\(x^2 - 1\)[/tex]).

Factor the numerator:
The expression [tex]\(x^3 - 1\)[/tex] can be factored using the difference of cubes formula:
[tex]\[ a^3 - b^3 = (a - b)(a^2 + ab + b^2) \][/tex]
In our case, [tex]\(a = x\)[/tex] and [tex]\(b = 1\)[/tex]:
[tex]\[ x^3 - 1 = (x - 1)(x^2 + x + 1) \][/tex]

Factor the denominator:
The expression [tex]\(x^2 - 1\)[/tex] can be factored using the difference of squares formula:
[tex]\[ a^2 - b^2 = (a - b)(a + b) \][/tex]
In our case, [tex]\(a = x\)[/tex] and [tex]\(b = 1\)[/tex]:
[tex]\[ x^2 - 1 = (x - 1)(x + 1) \][/tex]

### Step 2: Rewrite the Expression with Factored Forms
Substitute the factored forms of the numerator and denominator into the original expression:
[tex]\[ \frac{x^3 - 1}{x^2 - 1} = \frac{(x - 1)(x^2 + x + 1)}{(x - 1)(x + 1)} \][/tex]

### Step 3: Simplify the Expression
We can now cancel the common factor [tex]\((x - 1)\)[/tex] in the numerator and the denominator (assuming [tex]\(x \neq 1\)[/tex]):
[tex]\[ \frac{(x - 1)(x^2 + x + 1)}{(x - 1)(x + 1)} = \frac{x^2 + x + 1}{x + 1} \][/tex]

### Step 4: Examine the Simplified Expression
The simplified expression is [tex]\(\frac{x^2 + x + 1}{x + 1}\)[/tex]. It does not simplify further to [tex]\(x\)[/tex].

To determine whether [tex]\(\frac{x^2 + x + 1}{x + 1} = x\)[/tex], you can examine it more closely:
For the expression [tex]\(\frac{x^2 + x + 1}{x + 1}\)[/tex] to equal [tex]\(x\)[/tex]:
[tex]\[ x \neq -1 \][/tex]
both sides of the equation [tex]\(\frac{x^2 + x + 1}{x + 1} = x\)[/tex] should hold:

Set up the equation:
[tex]\[ \frac{x^2 + x + 1}{x + 1} = x \][/tex]
Cross multiply to solve for [tex]\(x\)[/tex]:
[tex]\[ x^2 + x + 1 = x \cdot (x + 1) \][/tex]
[tex]\[ x^2 + x + 1 = x^2 + x \][/tex]
Subtract [tex]\(x^2 + x\)[/tex] from both sides:
[tex]\[ 1 = 0 \][/tex]

### Conclusion
Clearly, the above equation [tex]\(1 = 0\)[/tex] is a contradiction, which means [tex]\(\frac{x^2 + x + 1}{x + 1} \neq x\)[/tex].

So, [tex]\(\frac{x^3 - 1}{x^2 - 1} \neq x\)[/tex].

Therefore, the correct answer is:
No, because the simplified form of the expression [tex]\(\frac{x^3 - 1}{x^2 - 1}\)[/tex] is [tex]\(\frac{x^2 + x + 1}{x + 1}\)[/tex] and it doesn't simplify to [tex]\(x\)[/tex].