Bài 2 :
a) `(2x-4)³=8`
`(2x-4)³=2³`
`⇒ 2x - 4=2`
`⇒2x = 6`
`⇒x = 6:2 = 3`
b) `720 : (41-(2x-5)) =2³.5`
`⇒ 720:(41- (2x-5)) = 8.5`
`⇒ 720:(41-(2x-5))=40`
`⇒ 41-(2x-5)=720:40`
`⇒ 41-(2x-5)=18`
`⇒ 2x-5=40-18`
`⇒ 2x-5=22`
`⇒ 2x=27`
`⇒ x=13,5`
Xin ctlhn ~