1) State the domain restrictions for the following polynomials:

x
x-4
a)
b)
c)
x- 8
x2(x+3)
x+7 5-x
d)
3x-5 x245246
Operations with Rational Expressions - simplify the following:
5
2)
+
x+3
x-2
3)
x-5x x2-3x-10
.
x2-4 x2+4x-12
3x2
5
4)
3x-6x
x
5) Solve the following:
x 5 x2+2x-8
+
4
x 2
-
=
1
x 2
-
write normally not bullet points only the occasional numbers needed to number the problum

1 answer

  1. 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 \( x = 3 \).

  1. Simplifying the following rational expressions:

  2. \( \frac{5}{x + 3} + \frac{x - 2}{3} \)

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 \( \frac{x^2 + 3x + 9}{3(x + 3)} \).

  1. \( \frac{x - 5x}{x^2 - 3x - 10} \)

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:

\[ \frac{-4x}{(x - 5)(x + 2)} \]

  1. \( \frac{3x^2 - 6x}{x^2 + 4x - 12} \)

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:

\[ \frac{3x}{x + 6} \quad \text{(for } x \neq 2\text{)} \]

  1. 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.

  1. We go through each step methodically for accurate results.