`#3107.101107`
`(3x - 4)^3 = 5^2 + 4*5^2`
`\Rightarrow (3x - 4)^3 = 5^2 * (1 + 4)`
`\Rightarrow (3x - 4)^3 = 5^2 * 5`
`\Rightarrow (3x - 4)^3 = 5^3`
`\Rightarrow 3x - 4 = 5`
`\Rightarrow 3x = 5 + 4`
`\Rightarrow 3x = 9`
`\Rightarrow x = 9 \div 3`
`\Rightarrow x = 3`
Vậy, `x = 3.`
\((3x-4)^3=5^2+4\cdot5^2\\\Rightarrow(3x-4)^3=5^2\cdot(1+4)\\\Rightarrow(3x-4)^3=5^2\cdot5\\\Rightarrow(3x-4)^3=5^3\\\Rightarrow3x-4=5\\\Rightarrow3x=5+4\\\Rightarrow3x=9\\\Rightarrow x=9:3\\\Rightarrow x=3\)