(4x²-20x+18)/(x²-5x+4)≥3
(4x²-20x+18)/(x²-5x+4)-3≥0
(4x²-20x+18-3x²+15x-12)/(x²-5x+4)≥0
(x²-5x+6)/(x²-5x+4)≥0
(x-2)(x-3)/[(x-1)(x-4)]≥0
x>4或2≤x≤3或x<1