​$$(x + y) (x + y)$$​​

​$$(x + y) (x – y)$$​​

​$$(x – y) (x – y)$$​​

​$$(y + x) (y – x)$$​​

​​​$$\left(a+b\right)^2-\left(a-b\right)^2$$​​

​​​$$\left(a-b\right)^2-\left(a+b\right)^2$$​​

​​​$$\frac{\left(a+b\right)^2}{2}+\frac{\left(a-b\right)^2}{2}$$​​

​​​$$\left(\frac{a+b}{2}\right)^2-\left(\frac{a-b}{2}\right)^2$$​​

​$$x = a^n$$​​

​$$x = Inx$$​​

​$$a = x^n$$​​

​$$x\:=\:\log _an$$​​

​$$x² – y²$$​​

​$$x + y$$​​