@carmelogugliotta
Proprietà distributiva
$\left ( \left [ \dfrac{19^5}{19^3} -\dfrac{19^3}{19^3} - \dfrac{17^4}{17^2} +\dfrac{17^3}{17^2}-\dfrac{17^2}{17^2} +3\right ]^2 \div 18^2 + (2^5 -3^3)^2 \right )^2 =$
Proprietà delle potenze
$([19^2 - 1 -17^2 +17 -1 +3 ]^2 \div 18^2 + (2^5 -3^3)^2 )^2=$
$([(17+2)^2 - 17^2 +17 + 1]^2 \div 18^2 + (2^5 -3^3)^2)^2=$
$([17^2 + 4 +2\cdot 2\cdot 17 -17^2+18]^2 \div 18^2 + (2^5 -3^3)^2)^2=$
$(( 4\cdot 17 +22)^2 \div 18^2 + (2^5 -3^3)^2)^2=$
$\left (\dfrac{90^2}{18^2} + 5^2 \right )^2=$
$\left ( \left (\dfrac{90}{18} \right )^2 + 25 \right )^2=$
$50^2$
Spero di non essermi perso qualche pezzo per strada