How do you factor completely #a^2 - ab - a + b#?

1 Answer
Apr 6, 2016

Answer:

# =color(green)( (a -1 ) ( a -b) #

Explanation:

#a^2 - ab - a + b#

Factorising by grouping:

We can factor this expression by making groups of two terms:
#(a^2 - ab) + ( - a + b)#

#a# is common to both the terms in the first group, and #-1# is common to both the terms in the second group:

# = a( a -b) - 1(a-b)#
#a-b# is common to both the terms now:

# =color(green)( (a -1 ) ( a -b) #