An equation which is true for all real values of its variables is called an
identity. This is denoted by the symbol "º"

Example:
Show that the equation (a-b)^{2} = a^{2} - 2ab + b^{2} is an identity. Solution:
Substituting a = 2 and b =1 in the equation,
LHS = (2-1)^{2} = 1^{2 }= 1
RHS = 2^{2 }- 2.2.1 + 1^{2 }
= 4 - 4 + 1
= 1
LHS = RHS. Hence equation is true for values 2 and 1.
Similarly it can be proved that the equation becomes a true statements for
any pair of real numbers

Direction: Show that the following equations are
in identities or not, taking any pair of real numbers and prove.