1.Moi tap hop sau co bao nhieu phan tu
a)A={x€N/x-8=10}
b)B={x€N/x+5=5}
c)C={x€N/x×0=0}
d)D={x€N/5<x<6}
2.Viet tat ca cac tap hop con (khac rong )cua tap hop B:B={a,b,c}
3.Cho tap hop A={10,13,16,.......,100}
a)Tinh so phan tu cua tap hop A.
b)Tinh tong cac phan tu cua A.
Nho giup minh nha