Question:
Which of the following is correct?
(a) (a – b)2 = a2 + 2ab – b2
(b) (a – b)2 = a2 – 2ab + b2
(c) (a – b)2 = a2 – b2
(d) (a + b)2 = a2 + 2ab – b2
Solution:
(b) (a – b)2 = a2 – 2ab + b2
We have, = (a – b) × (a – b)
= a × (a – b) – b × (a – b)
= a2 – ab – ba + b2
= a2 – 2ab + b2