Nomor 5-7 gimana ya kak caranya

5).(√3+√2) (√6-√2)=(1,7+1,4) (2,4-1,4)
                             =3,1*1,4
                             =4,34
6).(5√2+√3) (√2-3√3)=(5*1,4+1,7) (1,4-3*1,7)
                                 =(7+1,7) (1.4-5,1)
                                 =8,7*-3.7
                                 =32,19