Question

va rooog ajutati-mă si pe mine .

Answer 1

21.a)20+2√5×[2√300+2×(3√45-2√75)]=20+2√5×[2×10√3+2×(3×3√5-2×5√3)]
=20+2√5×[20√3+2×(9√5-10√3)]=20+2√5×(20√3+18√5-20√3)=
=20+2√5×18√5=20+2×5×18=20+180=200

b)80+5√3×[6×6√2+3×(4×4√3-3×4√2)]=80+5√3×[36√2+3×(16√3-12√2)]=
=80+5√3×(36√2+48√3-36√2)=80+5√3×48√3=80+5×3×48=80+720=800

c)80+4√5×{√3+[5√5-√15×(4√5-5√3)]}=
80+4√5×[√3+(5√5-√15×(4√5-5√3)]=80+4√5×[√3+(5√5-4√75+5√45)]=
=80+4√5×[√3+(5√5-4×5√3+5×3√5)]=80+4√5×[√3+(5√5-20√3+15√5)]=
=80+4√5×(√3+20√5-20√3)=
=80+4√5×(-19√3+20√5)=
=80-76√15+400=
480-76√15