Question

Use the grouping method to factor this polynomial completely. 2x 3 + 6x 2 + 5x + 15

Answer 1

Answer:

A

Step-by-step explanation:

Group the 4 terms into groups of 2 without changing their order.  That looks like this:

$(2x^3+6x^2)+(5x+15)$

Now within each group pull out what's common:

$2x^2(x+3)+5(x+3)$

Now we have (x + 3) common between the 2 terms, so let's pull that out.  With grouping, you know that it "works" if what's in the parenthesis are both exactly the same term.  Ours are both (x + 3).  What's "left over" are the things we originally pulled out, so group those together and you're done!

$(x+3)(2x^2+5)$