4x^2-4x-15≥0(2x+3)(2x-5)≥0x≥5/2或x≤-3/2x≥5/2时绝对值2x+3在+上根号下4x方-20x+25=(2x+3)+√(2x-5)^2=(2x+3)+(2x-5)=4x-2x≤-3/2时绝对值2x+3在+上根号下4x方-20x+25=-(2x+3)+√(2x-5)^2=-(2x+3)+(5-2x)=2-4x...