An example of the difference of squares would be: a^2-b^2 = (a+b)(a-b)
Answer:
Given expression :
......[1]
Using distributive property: 
[1]⇒ 
Simplify:

Like terms are those terms which are same variables.
Combine like terms: we get;
......[2]

Simplify:
or
we can write equation [2] as;
Combine like terms of x variables;
Therefore, the expressions which are equivalent to the Given expression are:

Positive because a function is beetween and past