- Domain restrictions for the following polynomials:
a) \( x \): There are no restrictions; the domain is all real numbers, \( \mathbb{R} \).
b) \( x - 4 \): There are no restrictions; the domain is all real numbers, \( \mathbb{R} \).
c) \( x - 8 \): There are no restrictions; the domain is all real numbers, \( \mathbb{R} \).
d) \( x^2(x + 3) \): There are no restrictions; the domain is all real numbers, \( \mathbb{R} \).
e) \( \frac{x + 7}{5 - x} \): The restriction is \( 5 - x \neq 0 \) which implies \( x \neq 5 \). The domain is all real numbers except \( x = 5 \).
f) \( \frac{3x - 5}{x^2 - 5x + 6} \): The restriction comes from setting the denominator equal to zero: \( x^2 - 5x + 6 = 0 \), which factors to \( (x - 2)(x - 3) = 0 \). Therefore, \( x \neq 2 \) and \( x \neq 3 \). The domain is all real numbers except \( x = 2 \) and \( x = 3 \).
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Simplifying the following rational expressions:
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\( \frac{5}{x + 3} + \frac{x - 2}{3} \)
To add these fractions, we need a common denominator, which will be \( 3(x + 3) \):
\[ \frac{5 \cdot 3}{3(x + 3)} + \frac{(x - 2)(x + 3)}{3(x + 3)} = \frac{15 + (x^2 + 3x - 2x - 6)}{3(x + 3)} = \frac{x^2 + 3x + 9}{3(x + 3)} \]
So, the simplified result is \( \frac{x^2 + 3x + 9}{3(x + 3)} \).
- \( \frac{x - 5x}{x^2 - 3x - 10} \)
This simplifies to:
\[ \frac{-4x}{x^2 - 3x - 10} \]
Factoring the denominator gives us \( x^2 - 3x - 10 = (x - 5)(x + 2) \):
So, the expression becomes:
\[ \frac{-4x}{(x - 5)(x + 2)} \]
- \( \frac{3x^2 - 6x}{x^2 + 4x - 12} \)
First, factor both the numerator and the denominator:
Numerator: \( 3x(x - 2) \)
Denominator: \( (x - 2)(x + 6) \)
This results in:
\[ \frac{3x(x - 2)}{(x - 2)(x + 6)} \]
Cancelling the \( (x - 2) \) term, we get:
\[ \frac{3x}{x + 6} \quad \text{(for } x \neq 2\text{)} \]
- Solve the following equation:
\[ \frac{x}{5} + \frac{x^2 + 2x - 8}{4x^2} = \frac{1}{x^2} \]
Finding a common denominator, we have:
\[ \frac{4x^2 \cdot x + 4(x^2 + 2x - 8)}{20x^2} = \frac{20}{20x^2} \]
Multiplying through by \( 20x^2 \) yields:
\[ 4x^3 + 4(x^2 + 2x - 8) = 20 \]
Distributing gives:
\[ 4x^3 + 4x^2 + 8x - 32 = 20 \]
Rearranging terms we have:
\[ 4x^3 + 4x^2 + 8x - 52 = 0 \]
Now, solve for \( x \) using techniques such as synthetic division, factoring, or numerical methods.
- We go through each step methodically for accurate results.