`a,`
`11 + 5^2 . (3 - x)^3 = 211`
`=> 11 + 25 . (3 - x)^3 = 211`
`=> 25 . (3 - x)^3 = 211 - 11`
`=> 25 . (3 - x)^3 = 200`
`=> (3 - x)^3 = 200 : 25`
`=> (3 - x)^3 = 8`
`=> (3 - x)^3 = 2^3`
`=> 3 - x = 2`
`=> x = 3 - 2`
`=> x = 1`
Vậy `x = 1`
`b,`
`5 + 2 . (x - 4)^3 = 59`
`=> 2 . (x - 4)^3 = 59 - 5`
`=> 2 . (x - 4)^3 = 54`
`=> (x - 4)^3 = 54 : 2`
`=> (x - 4)^3 = 27`
`=> (x - 4)^3 = 3^3`
`=> x - 4 = 3`
`=> x = 3 + 4`
`=> x = 7`
Vậy `x = 7`
`c,`
`2^3 . (3 - x) - 3^2 = 4^2`
`=> 8 . (3 - x) - 9 = 16`
`=> 8 . (3 - x) = 16 + 9`
`=> 8 . (3 - x) = 25`
`=> 3 - x = 25 : 8`
`=> 3 - x = 25/8`
`=> x = 3 - 25/8`
`=> x = (-1)/8`
Vậy `x = (-1)/8`
