word request - What is the right term to indicate the opposite of the math operation distribution?

I am studying math, and there's a term I don't know how to express, I just know that is the opposite of the operation of distribution of terms in an algebraic expression. For example, from the basic math operations we all learnt at primary school:

(a + b) * 3

... and if I distribute (distribution) the 3, I get:

3*a + 3*b

Now, what is the technical English name and verb for the reverse operation:

3(a + b)

?

Answer

The word for this is "factoring". "Factor" can be used as a verb, just like "distribute". When you do this:

3*a + 3*b

3(a + b)

you are factoring out the 3. (Present tense: "factor out the three".) When you do this:

x^2 + 5x + 6 = (x + 2)(x + 3)

you are factoring the polynomial.

"Factor" is also a noun. When you do this

100 = 2 * 2 * 5 * 5

you are finding the prime factors of 100.

"Distribute" is mainly used as a verb. When you do this:

5(a + b) = 5*a + 5*b

You are distributing the 5. But you can't call the 5s "distributors" or anything like that.

The property of multiplication and addition that allows you to do all this is called the distributive property.