`b) [ 22,5 - ( 2/3 + 4/5) x ] : 2/3 - 75% = 0`
`[45/2 - ( 2/3 + 4/5) x] : 2/3 - 3/4 = 0`
`[45/2 - ( 2/3 + 4/5) x] : 2/3 = 0 + 3/4`
`[45/2 - ( 2/3 + 4/5) x] : 2/3 = 3/4`
`[45/2 - 22/15 x] = 3/4 . 2/3`
`45/2 - 22/15 x = 1/2`
`22/15 . x = 45/2 - 1/2`
`22/15 . x = 22`
`x = 22 : 22/15`
`x= 15`
Vậy `x = 15`