√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.
b1*q^2=12
b1*q^4=b5
48*q^2=12*q^4
4q^2=q^4
q^2=4
q=2