Question

guys in this type of question is it compulsory to use (a-b)²=a²-2ab+b²​
can we do it in the normal way/directly without using this formula​

Answer 1

Answer:

yes...as the question says to use identity.

Answer 2

Answer:

No, Its necessary to use that identity as it is is given in question use suitable identity.

In Q.C else u can use $x^{2} -y^{2} =(x+y)(x-y)$

Hope this helps you.