`text{Đáp án:}`
`x = 1`
$\left[\begin{matrix} x=2\\ x=(-4)\end{matrix}\right.$
`text{Giải thích các bước giải:}`
`(3x-1)(2x+7)-(x+1)(6x-5)=16`
`6x^2+21x-2x-7-(6x^2-5x+6x-5)=16`
`6x^2+21x-2x-7-6x^2+5x-6x+5=16`
`18x-2=16`
`18x=16+2`
`18x=18`
`x = 18 : 18`
`x=1`
`- - - - - -`
`(x^4+2x^3+10x-25):(x^2+5)=3`
`(x^4 - 25) + (2x^4 + 30x) : 2x + 5 = 3`
`(x^2 - 5)(x^2 + 5) + 2x(x^2 + 5) : x^2 + 5 = 3`
`(x^2 + 5)(x^2 - 5 + 2x) : x^2 + 5 = 3`
`x^2 - 5 + 2x = 3`
`x^2 + 2x + 1 - 6 = 3`
`(x + 1)^2 = 9`
`(x + 1)^2 = 3^2`
`=>` $\left[\begin{matrix}x+1=3\\x+1=(-3)\end{matrix}\right.$
`=>` $\left[\begin{matrix}x=3-1\\x=(-3)-1\end{matrix}\right.$
`=>` $\left[\begin{matrix}x=2\\x=(-4)\end{matrix}\right.$
