How do you factor #4x - x^2 - 4y + xy# completely?

1 Answer
Oct 7, 2016

Answer:

#(4-x)(x-y)#

Explanation:

Factorise by #color(blue)"grouping the terms"# as follows.

#[4x-x^2]+[-4y+xy]#

now factorise each group.

#rArrcolor(red)(x)color(blue)((4-x))color(red)(-y)color(blue)((4-x))#

We now have a common factor of (4 - x).

#rArrcolor(blue)((4-x))color(red)((x-y))#

#rArr4x-x^2-4y+xy=(4-x)(x-y)#