Câu 7:
1/ Ư(10)={±1,±2,±5,±10}
2/B(-15)={0,±15,±30,±45,±60,....}
3/Ư(-24)={±1,±2,±3,±4,±6,±8,±12,±24}
4/ƯC(-12,18)
Ta có: 12=2²x3; 18=2x3²
=>ƯCLN(-12,18)=2²x3²=36
=>ƯC(-12,18)={±1,±2,±3,±4,±6,±9,±12,±18,±36}
5/BC(-15,+20)
Ta có: 15=3x5; 20=2²x5
=>BCNN(-15.+20)=2²x3x5=60
=>BCNN(-15,+20)={0,±60,±120,±180,±240,...}
Cho mik ctlhn nhé!!!!!!!!!!!