Tick (✓) the correct answer

Question:

Tick (✓) the correct answer:

ab − a − b + 1 = ?

(a) (a − 1)(b − 1)

(b) (1 − a)(1 − b)

(c) (a − 1)(1 − b)

(d) (1 − a)(b − 1)

Solution:

(a) (a − 1)(b − 1)

$a b-a-b+1$

$=a(b-1)-1(b-1)$

$=(a-1)(b-1)$

 

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