\(=\left[x^2\left(2x-5\right)+3\left(2x-5\right)\right]:\left(2x-5\right)\\ =x^2+3\)
\(\left(2x^3-5x^2+6x-15\right):\left(2x-5\right)\\ =\left[x^2\left(2x-5\right)+3\left(2x-5\right)\right]:\left(2x-5\right)\\ =\left[\left(2x-5\right)\left(x^2+3\right)\right]:\left(2x+5\right)=x^2+3\)