Math Help - Common Factors

1. Common Factors

Factor by grouping

xy + 12 + 4x + 3y = (x+3)(4+y)<-------txtbk ans

x² + x - xy - y = (x+1)(x-y)<--------txtbk ans

2. $xy + 12 + 4x + 3y$

$xy + 3y + 4x+ 12$

$y(x + 3) + 4(x+ 3)$

$(x + 3)(y+4)$

Do you follow?

3. Originally Posted by pickslides
$xy + 12 + 4x + 3y$

$xy + 3y + 4x+ 12$

$y(x + 3) + 4(x+ 3)$

$(x + 3)(y+4)$

Do you follow?
Do you always have to rearrange the expression before solving?

Can't it also say x(y+4)+3(4+y) in the 3rd step?

And how would you know to group which ones together?

4. Originally Posted by larry21
Do you always have to rearrange the expression before solving?
Only so you can take out a common factor.

Originally Posted by larry21
Can't it also say x(y+4)+3(4+y) in the 3rd step?