Bài `2`
`a ) 128 - 3(x + 4) = 23`
`3(x + 4) = 128 - 23`
`3(x + 4) = 105`
`x + 4 = 105 : 3`
`x + 4 = 35`
`x = 35 - 4`
`x = 31`
`b ) [(4x + 28) . 3 + 55] : 5 = 35`
`(4x + 28) . 3 + 55 = 35 . 5`
`(4x + 28) . 3 + 55 = 175`
`(4x + 28) . 3 = 175 - 55`
`(4x + 28) . 3 = 120`
`4x + 28 = 120 : 3`
`4x + 28 = 40`
`4x = 40 - 28`
`4x = 12`
`x = 12 : 4`
`x = 3`
`c ) (12x - 4^3) . 8^3 = 4 . 8^4`
`(12x - 64) . 512 = 4 . 4096`
`(12x - 64) . 512 = 16384`
`12x - 64 = 16384 : 512`
`12x - 64 = 32`
`12x = 32 + 64`
`12x = 96`
`x = 96 : 12`
`x = 8`
`d ) 720 : [41 - ( 2x - 5)] = 2^3 . 5`
`720 : [41 - (2x - 5)] = 8 . 5`
`720 : [41 - (2x - 5)] = 40`
`41 - (2x - 5) = 720 : 40`
`41 - (2x - 5) = 18`
`2x - 5 = 41 - 18`
`2x - 5 = 23`
`2x = 23 + 5`
`2x = 28`
`x = 28 : 2`
`x = 14`
`e ) 123 - 5 . (x + 4) = 38`
`5 . (x + 4) = 123 - 38`
`5 . (x + 4) = 85`
`x + 4 = 85 : 5`
`x + 4 = 17`
`x = 17 - 4`
`x = 13`
`g ) (3x - 2^4 ) . 7^3 = 2 . 7^4`
`(3x - 16) . 343 = 2 . 2401`
`(3x - 16) . 343 = 4802`
`3x - 16 = 4802 : 343`
`3x - 16 = 14`
`3x = 14 + 16`
`3x = 30`
`x = 30 : 3`
`x = 10`
`#dtkc`