2x^4+3x^3-5x^2+3x+2
=2x^4+4x^2+2+3x^3+3x-9x^2
=2(x^2+1)^2+3x(x^2+1)-9x^2
=[2(x^2+1)-3x](x^2+1+3x)
=(2x^2-3x+2)(x^2+3x+1)望采纳哦