Factorize the following expressions:

xy – xz + ay – az

= xy – xz + ay – az
Taking x common in xy – xz

we get,

= x(y – z) + ay – az

Taking ‘a’ common in ay – az

we get,

= x(y – z) + a(y – z)
Taking (y – z) common in both the terms

we get,
= (y – z)(x + a)
xy – xz + ay – az = (y – z)(x + a)