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Question 16, 6.3.55
Factor completely.
-6 x^3+3 x^2+45 x
Select the correct choice below and fill in any answer boxes within your choice.
A. -6 x^3+3 x^2+45 x=
B. The polynomial is prime.
Transcript text: Pearson MyLab and Mas
Do Homework - Section
mylab.pearson.com
Question 16, 6.3.55
Factor completely.
\[
-6 x^{3}+3 x^{2}+45 x
\]
Select the correct choice below and fill in any answer boxes within your choice.
A. $-6 x^{3}+3 x^{2}+45 x=$ $\square$
B. The polynomial is prime.
Solution
Solution Steps
To factor the given polynomial completely, we first look for the greatest common factor (GCF) of all the terms. Then, we factor out the GCF and check if the remaining polynomial can be factored further.
Solution Approach
Identify the GCF of the terms in the polynomial.
Factor out the GCF.
Check if the remaining polynomial can be factored further.
Step 1: Identify the Polynomial
We start with the polynomial:
\[
-6x^3 + 3x^2 + 45x
\]
Step 2: Factor Out the Greatest Common Factor (GCF)
The GCF of the terms \(-6x^3\), \(3x^2\), and \(45x\) is \(-3x\). We factor this out:
\[
-6x^3 + 3x^2 + 45x = -3x(2x^2 - x - 15)
\]
Step 3: Factor the Quadratic Expression
Next, we need to factor the quadratic expression \(2x^2 - x - 15\). We can find two numbers that multiply to \(2 \cdot (-15) = -30\) and add to \(-1\). The numbers \(-6\) and \(5\) work:
\[
2x^2 - 6x + 5x - 15 = 2x(x - 3) + 5(x - 3) = (2x + 5)(x - 3)
\]
Step 4: Combine the Factors
Now we can write the complete factorization of the original polynomial:
\[
-6x^3 + 3x^2 + 45x = -3x(2x + 5)(x - 3)
\]
Final Answer
The complete factorization is:
\[
\boxed{-3x(2x + 5)(x - 3)}
\]