Formula use: \left(a-b\right)^3=a^3-3a^2b+3ab^2-b^3

Explanation

Here, given expression is :
\left(80\right)^3-3\times\left(80\right)^2\times20+3\times80\times\left(20\right)^2-\left(20\right)^3
Let’s
80 = a
20 = b
Now, find the value :
\left(80\right)^3-3\times\left(80\right)^2\times20+3\times80\times\left(20\right)^2-\left(20\right)^3
\rightarrow \left(a\right)^3-3.a^2.b+3.a.b^3-\left(b\right)^3
\rightarrow\left(a-b\right)^3
\rightarrow\left(80-20\right)^3
\rightarrow\left(60\right)^3
\therefore 1920
Ans: 1920 .