✓82²-18²=
✓65²-63²=
=✓113²-112²=
✓✓3⁴*2²=

√82²-18²= √(82-18)(82+18) =√64·100 =8·10=80.

√65²-63² =√(65-63)(65+63) =√2·128 =√2·2·64 =2·8=16.

√113²-112² =√1·225 =15.

√√3^4·2²=√3²·2 =3√2.