giúp......................................

Đáp án+Giải thích các bước giải:

`a)`

`200-(2x+6)=4^{3}` `(đk:x\inNN)`

`=>2x+6=200-4^{3}`

`=>2x+6=200-64`

`=>2x+6=136`

`=>2x=136-6`

`=>2x=130`

`=>x=130:2`

`=>x=65(tmđk)`

Vậy `x=65` 

`b)`

`2.(x-51)=2.2^{3}+20` `(đk:x\inNN)`

`=>2.(x-51)=2.(2^{3}+10)`

`=>2.(x-51)=2.(8+10)`

`=>2.(x-51)=2.18`

`=>x-51=18`

`=>x=18+51`

`=>x=69(tmđk)`

Vậy `x=69`

`c)`

`[(6x-39):7].4=12` `(đk:x\inNN)`

`=>(6x-39):7=12:4`

`=>(6x-39):7=3`

`=>6x-39=3.7`

`=>6x-39=21`

`=>6x=21+39`

`=>6x=60`

`=>x=60:6`

`=>x=10(tmđk)`

Vậy `x=10`

`d)`

`24.(x-16)=12^{2}` `(đk:x\inNN)`

`=>24.(x-16)=144`

`=>x-16=144:24`

`=>x-16=6`

`=>x=6+16`

`=>x=22(tmđk)`

Vậy `x=22`

`e)`

`(x^{2}-10):5=3` `(đk:x\inNN)`

`=>x^{2}-10=3.5`

`=>x^{2}-10=15`

`=>x^{2}=15+10`

`=>x^{2}=25`

`=>x^{2}=5^{2}=(-5)^{2}`

`=>x=5(tmđk)` hoặc `x=-5(ktmđk)`

Mà `x\inNN`

`=>x=5`

Vậy `x=5`