`#Sad`
`a)`
`[(8x-12) : 4]. 3 = 36`
`⇔ (8x-12) : 4 = 12`
`⇔ 8x-12 = 48`
`⇔ 8x = 60`
`⇔ x = (60)/8 = (15)/2`
`\text{Vậy}` `x=(15)/2`
`b)`
`41-2(x+1) = 21`
`⇔ 2(x+1) = 20`
`⇔ x+1 = 10`
`⇔ x = 9`
`\text{Vậy}` `x=9`
`d)`
`740 : (x+10) = 102-2. 13`
`⇔ 740 : (x+10) = 102-26`
`⇔ 740 : (x+10) = 76`
`⇔ x+10 = (185)/(19)`
`⇔ x = -(5)/(19)`
`\text{Vậy}` `x=-(5)/(19)`
`f)`
`720 : [41-(2x-5)] = 2^3. 5`
`⇔ 720 : [41-(2x-5)] = 8. 5`
`⇔ 720 : [41-(2x-5)] = 40`
`⇔ 41-(2x-5) = 18`
`⇔ 2x-5 = 23`
`⇔ 2x = 28`
`⇔ x = 14`
`\text{Vậy}` `x=14`