Use the grouping method to factor this polynomial completely.

[tex]\[2x^3 + 6x^2 + 5x + 15\][/tex]

A. [tex]\(\left(2x^2 + 3\right)(x + 3)\)[/tex]

B. [tex]\(\left(2x^2 + 5\right)(x + 5)\)[/tex]

C. [tex]\(\left(2x^2 + 5\right)(x + 3)\)[/tex]

D. [tex]\(\left(2x^2 + 3\right)(x + 5)\)[/tex]



Answer :

Sure, let's factor the polynomial [tex]\(2x^3 + 6x^2 + 5x + 15\)[/tex] using the grouping method step-by-step.

### Step 1: Grouping the Polynomial into Two Pairs

First, we group the terms:

[tex]\[ 2x^3 + 6x^2 + 5x + 15 = (2x^3 + 6x^2) + (5x + 15) \][/tex]

### Step 2: Factor Out the GCD (Greatest Common Divisor) from Each Group

Group 1: [tex]\(2x^3 + 6x^2\)[/tex]

In this group, we can factor out the common factor [tex]\(2x^2\)[/tex]:

[tex]\[ 2x^3 + 6x^2 = 2x^2(x + 3) \][/tex]

Group 2: [tex]\(5x + 15\)[/tex]

In this group, we can factor out the common factor [tex]\(5\)[/tex]:

[tex]\[ 5x + 15 = 5(x + 3) \][/tex]

### Step 3: Combine the Factored Terms

Now we have:

[tex]\[ 2x^3 + 6x^2 + 5x + 15 = 2x^2(x + 3) + 5(x + 3) \][/tex]

### Step 4: Factor Out the Common Binomial Factor

Notice that both terms now contain the common binomial factor [tex]\((x + 3)\)[/tex]:

[tex]\[ 2x^2(x + 3) + 5(x + 3) = (x + 3)(2x^2 + 5) \][/tex]

So, the polynomial can be factored completely as:

[tex]\[ 2x^3 + 6x^2 + 5x + 15 = (x + 3)(2x^2 + 5) \][/tex]

### Conclusion

The completely factored form of the polynomial [tex]\(2x^3 + 6x^2 + 5x + 15\)[/tex] is [tex]\((x + 3)(2x^2 + 5)\)[/tex], which corresponds to the correct answer option:

C. [tex]\(\left(2 x^2 + 5\right)(x + 3)\)[/tex]