Đáp án`+`Giải thích các bước giải:

`1)`

`a) [626 -(25 . 8 +26)]:8 -50` 

`=[626 -(200+26)]:8 -50`

`= [626 -226]:8 -50`

`=400 :8 -50`

`=50 -50`

`=0`

`b) 2023^0 +240 :[179 -(5 . 2^3 +179)]`

`=1 +240 :[179-(5 . 8 +179)]`

`=1+240:[179 -(40 +179)]`

`=1+240:[179 - 219]`

`=1+240:(-40)`

`=1 -6`

`=-5`

`c) (-105). 19 +(-76) . 105 -5 . 105`

`= 105 . (-19) - 76 . 105 -5 . 105`

`=105 . (-19 -76 -5)`

`=105 . (-100)`

`=-10500`

`2)`

`a) 34 +(x-1)^3=42`

`(x-1)^3=42-34`

`(x-1)^3=8`

`(x-1)^3=2^3`

`x-1=2`

`x=2+1`

`x=3`

Vậy `x=3`

`b) 2(x+3)-48:2^3=2`

`2(x+3)-48 :8=2`

`2(x+3)-6=2`

`2(x+3)=2+6`

`2(x+3)=8`

`x+3=8:2`

`x+3=4`

`x=4 -3`

`x=1`

Vậy `x=1`