12x²-3y²

计算 [12(x+y)³(y-x)]³÷[4(x+y)²（x-y)]² 化简 3(X-Y)²-4(X-Y)+7(X-Y)-6(X-Y)² 因式分解：(x-y)(3x-7y)²-4(x-y)(x+y)² 当x,y为实数,满足x²+3y²-12y+12=0求y^x 急![(3x+y)²-3(3x-y)(x+y)-(x-3y)(x+3y)]÷(2xy) (x-y)X(2x-2y)²X(3x-3y)² 计算6x³y^6÷(1/2)y³÷(-3x²y)-(12x^4y^6-8x²y^ 因式分解:x²(x-y)+(y-x) 计算3x[xy-2x(1/y-x/3]+3y(x²-y²) (3x-y)²-2x（4x-5y）-（x+2y）² [x（x²y²-xy）-y（x²-x³y）]÷3x²y 【x(x²y²-xy)-y(x²-x³y)】÷3x²y