Помогите в В5 и В7 желательно письменно!!!

B5. =(3n^4/4m²) *(8m^3/n²) =(3n^4 *8m^3) /(4m²n²) =3n² *2m =6mn²

B7. √98 =√(7²*2) =7√2
√72 =√(2^3*3²) =3*2√2 =6√2
√8 =√(2²*2) =2√2

7√2 -6√2 +2√2 =√2(7 -6 +2) =3√2