To factor a+bx+c, you have to group it as (a+ux)+(vx+c) so that uv=ac and u+v=b. Both addition and multiplication are commutative, so how do you determine which value is assigned to u and which to v? Or are they interchangeable?

I'm not sure.  Try asking Google.  

Pl give me Brainliest  

For example, let's expand out (x+3)*(2x+1). Use of the FOIL rule should get to you 2x^2 + 7x + 3.

Now imaging that you handed 2x^2 + 7x + 3 to a friend to be factored. They do not know the factorization yet.

They would see that a = 2, b = 7, c = 3.

The friend needs to find two numbers u,v such that they multiply to a*c = 2*3 = 6 and add to b = 7

Through trial and error (I recommend making a table of values), your friend would get

But as you mentioned, your friend could easily swap the order of addition and multiplication to say

If we go with the first option, then the factor by grouping looks like this

2x^2 + 7x + 3

2x^2 + 1x + 6x + 3 ... break up 7x into 1x+6x

(2x^2+1x) + (6x+3) group up the terms into pairs

x(2x+1) + 3(2x+1) factor each grouping

(x+3)(2x+1) factor out the overall GCF

Or we could have the factor by grouping looks like this

2x^2 + 7x + 3

2x^2 + 6x + 1x + 3 ... break up 7x as 6x+1x

(2x^2+6x) + (1x+3)

2x(x+3) + 1(x+3)

(2x+1)(x+3)

(x+3)(2x+1)

We end up with the same factorization.