Factorize each of the following expressions:
(i)`a^2-b+a ba` (ii) `x y-a b+b x-a y`

Explanation

Given:

`(i) a^2-b+a b-a`

`=> (a^2+ab-b-a)`

`=>a(a+b)-1(b+a)`

`=>(a+b)(a-1)`

(ii) `x y-a b+b x-a y`

`=> (xy+bx-ab-ay)`

`=> x(y+b)-a(b+y)`

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