Q2 of 105 Page 274

Factories the following

(x + y)2 – (x – y)2

In the given expression


We know that


(a + b)2 = a2 + 2ab + b2


(a-b)2 = a2-2ab + b2


Hence


If a = x and b = y


(x + y)2 – (x – y)2 = x2 + y2 + 2xy – [x2 + y2-2xy]


= x2 + y2 + 2xy -x2-y2 + 2xy


= 4xy


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