Đáp án+Giải thích các bước giải:
`a,-4<x<3`
`=>x in {-3,-2,-1,0,1,2}`
`b,-5<x<5`
`=>x in {-4,-3,-2,-1,0,1,2,3,4}`
`c,-17<x<18`
`=>x in {-16,-15,-14,-13,-12,-11,-10,-9,-8,-7,-6,-5,-4,-3,-2,-1,0,1,2,3,4,5,6-7,8,9,10,11,12,13,14,15,16,17}`
`|x|<25`
`=>|x| in {0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16,17,18,19,20,21,22,23,24}`
`=>x in {0,+-1,+-2,+-3,+-4,+-5,+-6,+-7,+-8,+-9,+-10,+-11,+-12,+-13,+-14,+-15,+-16,+-17,+-18,+-19,+-20,+-21,+-22,+-23,+-24}`