ai 1. Rút gọn các phân thức sau: a) 14xy (2x-3y) 21xy(2x-3y) b) 8xy(3x-1)* 12x'(1-3x) 20x²-45 (2x+3)² d) 5x-10xy 9-(x+5)² 2(2y-x)³ e) 80x-125x 3(x-3)-(x-3)(8-4x) f) x²+4x+4 32x-8x²+2x³ x +5 +6 g) +64 h) i) x²+4x+4 J) 10xy² (x + y) 3x²-12x+12 k) x²-xy-x+y 1) 15xy(x+y) x-8x x²+xy-x-y 7x² ...