Question

Factorize the following expression ab-a-b+1

Answer 1

Group 'em together

a b − a + 1 − b

a b − a = a ( b − 1 )

Notice that there will be a 1 as without it it'll simply be  ab

1 − b = 1 ( 1 − b )

Notice that it doesn't match with the upper one... so we'll change the signs

1 ( 1 − b ) = − 1 ( b− 1 )

(try to multiply them now!!

Jot them down in one expression

a ( b − 1 ) − 1 ( b − 1 )

You get!!!!!!

( a − 1 ) ( b − 1 )