Giải nhanh giúp mik nha

`a)x-36:18=12-15`

`x-2=-7`

`x=-7+2`

`x=-5`

`b)92-(17+x)=72`

`17+x=92-72`

`17+x=20`

`x=20-17`

`x=3`

`c)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=18`

`x=18:2`

`x=9`

`d)(x+2)^3-23=41`

`(x+2)^3=41+23`

`(x+2)^3=64`

`(x+2)^3=4^3`

`=>x+2=4`

`=>x=4-2`

`=>x=2`

`e)70vdotsx;84vdotsx;140vdotsx` và `x>8`

`=>x in ƯC(70;84;140)`

Ta có :

`70=2.5.7`

`84=2^2. 3.7`

`140=2^2. 5.7`

`=>ƯCLN(70;84;140)=2.7=14`

`=>Ư(14)=ƯC(70;84;140)={1;2;7;14}`

Mà `x>8`

`=>x=14`