7th Class
Mathematics
Algebraic Expressions
Question Bank
Algebra
question_answer
Consider the following algebraic identities. (i) \[{{(a+b)}^{2}}={{a}^{2}}+2ab+{{b}^{2}}\] (ii) \[{{(a-b)}^{2}}={{a}^{2}}-2ab+{{b}^{2}}\] (iii) \[{{a}^{2}}-{{b}^{2}}=(a-b)\,(a+b)\] (iv) \[(a+x)(a+y)={{a}^{2}}+a(x+y)+xy\] Which of the identity is/are incorrect?