Hello all,

So far I have a fairly good understanding of factoring two and three term polynomials (I thought I did). I can find the GCF and understand how it applies. I've been solving the following types of problems through my homework: -9a^{5 }+ 18a^{2 }- 3a = -3a(3a^{4 }- 6a + 1) and 5x^{4} - 20x = 5x (x^{3 }- 4).

But textbook suddenly showed:**Factor:** 5(x + 3) + y(x + 3)

*Solution*:

The binomial (x + 3) is the greatest common factor. Use the distributive property to factor out (x + 3).

5(x + 3) + y(x + 3) = (x + 3) (5 + y)

**My problem:**

I don't understand how (x + 3) is a factor because so far, I've only see factors to be whole numbers and variables. How do you find a GCF from (x + 3)?? Is this an example of factoring by grouping? That's in the next section so I haven't covered that yet.

I really want to understand this section before I get back into class so that my professor's examples make more sense.

Thank you.