Write the polynomial expression in simplest form: 5x-20/x^2-9 * x^2 +12+27/x^2 +2x -24




The simplified form is
(Keep answer in factored form.)

What are the restrictions on the variable?
(Type only the numbers and separate your answers with commas, if needed.)

1 answer

Let's simplify the expression step by step. The given expression is:

\[ \frac{5x - 20}{x^2 - 9} \cdot \left( x^2 + 12 + \frac{27}{x^2 + 2x - 24} \right) \]

Step 1: Factor the components

1. Factor \(5x - 20\): \[ 5x - 20 = 5(x - 4) \]

2. Factor \(x^2 - 9\): \[ x^2 - 9 = (x - 3)(x + 3) \quad (\text{difference of squares}) \]

3. Simplify \(x^2 + 12 + \frac{27}{x^2 + 2x - 24}\):

  • First, factor \(x^2 + 2x - 24\): \[ x^2 + 2x - 24 = (x + 6)(x - 4) \]

  • Now, rewrite \(x^2 + 12\) over the same denominator: \[ x^2 + 12 = \frac{(x^2 + 12)(x + 6)(x - 4)}{(x + 6)(x - 4)} \]

Combining it gives: \[ \frac{(x^2 + 12)(x + 6)(x - 4) + 27}{(x + 6)(x - 4)} \]

Step 2: Combine Fractions

To combine these fractions, we need to fit everything under a common denominator:

\[ x^2 + 12 + \frac{27}{(x + 6)(x - 4)} = \frac{(x^2 + 12)(x + 6)(x - 4) + 27}{(x + 6)(x - 4)} \]

Step 3: Combine Everything

Combine everything into one expression:

\[ \frac{5(x - 4)}{(x - 3)(x + 3)} \cdot \frac{(x^2 + 12)(x + 6)(x - 4) + 27}{(x + 6)(x - 4)} \]

Step 4: Simplify

Looking at our expression, we can cancel \(x - 4\) from the numerator and denominator (note: \(x \neq 4\)):

\[ = \frac{5}{(x - 3)(x + 3)} \cdot \frac{(x^2 + 12)(x + 6) + \frac{27}{(x + 6)}} \]

Step 5: Identify Restrictions

The restrictions on the variable come from the denominators:

  1. From \(x^2 - 9\) i.e. \(x - 3 \neq 0\) and \(x + 3 \neq 0\), which gives \[ x \neq 3, , x \neq -3 \]
  2. From \(x^2 + 2x - 24\) i.e. \((x + 6)(x - 4) \neq 0\), which gives \[ x \neq -6, , x \neq 4 \]

Combining these restrictions, we get:

Final Restrictions:

\[ \text{Restrictions: } x \neq 3, -3, -6, 4 \]

Simplified Polynomial in Factored Form:

If \(x^2 + 12 = A\), you may evaluate further depending on expressions specifically about \(A\).

Thus the expression in its simplest factored form becomes:

\[ \frac{5((A)(x + 6) + 27)}{(x - 3)(x + 3)(x + 6)} \]

Simply writing the results:

  1. Simplified Expression: \[ \frac{5((x^2 + 12)(x + 6) + 27)}{(x - 3)(x + 3)(x + 6)} \]

  2. Restrictions: \[ -6, -3, 3, 4 \]