Question 430834
In identities there is a formula for the product of sum and difference of two variables.

(a+b)(a-b)=a^2-b^2

(s+t)(s-t)(s+t)(s-t)

{{{(s^2-t^2)(s+t)(s-t)}}}
{{{(s^2-t^2)(s^2-t^2)}}}
{{{(s^2-t^2)^2}}}

Another formula is (a-b)^2= a^2-2ab+b^2
here a= s^2 & b=t^2
{{{s^4-2s^2t^2+t^4}}}