`=(3x-1)^2+2(2x-1)(2x+5)+(2x+5)^2-(2x-3)(4x^2+6x+9):(2x-3)`
`=(3x-1)^2+2(2x-1)(2x+5)+(2x+5)^2-(2x-3)(4x^2+6x+9):(2x-3)`
`=(3x-1+2x+5)^2-(4x^2+6x+9)`
`=(5x+4)^2-(4x^2+6x+9)`
`=25x^2+40x+16-4x^2-6x-9`
`=21x^2+34x+7`
Ta có: \(\left(3x-1\right)^2-2\left(1-3x\right)\left(2x+5\right)+\left(5+2x\right)^2-\left(8x^3-27\right):\left(2x-3\right)\)
\(=\left(3x-1+2x+5\right)^2-\left(4x^2+6x+9\right)\)
\(=\left(5x+4\right)^2-\left(4x^2+6x+9\right)\)
\(=25x^2+40x+16-4x^2-6x-9\)
\(=21x^2+34x+7\)