Powers and Indices

The expression $\large 20172016^2- 2(20172016)(20172019) + 20172019^2$ can be stated as $a^2 - 2ab + b^2 = (a-b)^2$

Where $a= 20172016$ and $b = 20172019$

Hence $(20172016- 20172019)^2$ = $(-3)^2$ = $3^2$ = $\boxed{9}$ (Answer)

$if\quad { 20172016 }=t\quad \qquad the\quad expression\quad can\quad be:\\ t^{ 2 }-2t\left( t-3 \right) +\left( t-3 \right) ^{ 2 }=\left( t-\left( t-3 \right) \right) ^{ 2 }=\left( t-t+3 \right) ^{ 2 }=\boxed { 9 }$