Rational Expressions & Equations Unit Test

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Question
Express in simplest form: 5x2+10xx2+7x+12÷x2−4x2+x−6 .(1 point)
Responses

5x+4
Start Fraction 5 over x plus 4 End Fraction

5xx+4
Start Fraction 5 x over x plus 4 End Fraction

x+45x
Start Fraction x plus 4 over 5 x End Fraction

54

1 answer

To simplify the expression \( \frac{5x^2 + 10x^2 + 7x + 12}{x^2 - 4x^2 + x - 6} \), we first need to correct the denominator because the expression given seems off.

Let's clarify the expression and simplify each part:

Step 1: Combine Like Terms

The numerator is: \[ 5x^2 + 10x^2 + 7x + 12 = 15x^2 + 7x + 12 \]

The denominator can be simplified. Assuming the expression was intended as \( x^2 - 4x + x - 6 \) and combining the like terms yields: \[ (x^2 + x - 4x - 6) = (x^2 - 3x - 6) \]

So now our expression is: \[ \frac{15x^2 + 7x + 12}{x^2 - 3x - 6} \]

Step 2: Factor the Numerator and Denominator

To factor the numerator \( 15x^2 + 7x + 12 \):

We look for two numbers that multiply to \( 15 \times 12 = 180 \) and add to \( 7 \). The pair \( 15 \) and \( 12 \) doesn't seem to help easily.

Let's just use the quadratic formula to find its factors. The roots will be: \[ x = \frac{-b \pm \sqrt{b^2 - 4ac}}{2a} = \frac{-7 \pm \sqrt{7^2 - 4 \cdot 15 \cdot 12}}{2 \cdot 15} \] Calculating this gives complex factors, so we will leave it as is.

To factor the denominator \( x^2 - 3x - 6 \):

We can look for factors. This factors into: \((x - 6)(x + 1)\).

Final Expression:

Since we couldn't factor the numerator neatly, we are left with: \[ \frac{15x^2 + 7x + 12}{(x - 6)(x + 1)} \]

Unfortunately, we cannot simplify further without specific values for x.

Therefore among the responses given and based on workings, the correct answer from your options would be:

  1. None of the provided responses seem accurate regarding the function calculated above.

To summarize: Check the expressions given for correctness before choosing based on factors.