{x(2x-5)>2x^2-3x-4
{(x+1)(x+3)+8x>(x+5)(x-5)-2
得
{2x^2-5x>2x^2-3x-4
{x^2+4x+3+8x>x^2-25-2
{2x-40
{x-2.5
故-2.5