\(=\left(6x^3+9x^2-16x^2-24x+8x+12\right):\left(2x+3\right)\\ =\left(2x+3\right)\left(3x^2-8x+4\right):\left(2x+3\right)\\ =3x^2-8x+4\)
\(\left(6x^3-7x^2-16x+12\right):\left(2x+3\right)\\ =\left[\left(6x^3+9x^2\right)-\left(16x^2+24x\right)+\left(8x+12\right)\right]:\left(2x+3\right)\\ =\left[3x^2\left(2x+3\right)-8x\left(2x+3\right)+4\left(2x+3\right)\right]:\left(2x+3\right)\\ =\left[\left(2x+3\right)\left(3x^2-8x+4\right)\right]:\left(2x+3\right)\\ =3x^2-8x+4\)