AB是圆X^2+Y^2-6X+4Y-7=0的直径,若A=(1,2)求B的座标

下列等式的右边是怎样从左边得到的?2x(x-y)^7/4y(y-x)^6=x(x-y)/2y 圆C:x^2+y^2-2x-4y=0被直线L:3x-y-6=0截得弦为AB求AB 因式分解、谁来教教我这些题啊?1、(1+2ab)²-(2+2ab)²2、(7x+y)(7x-y)-(-x+y)(x-y)3、(x-2y-1)(x+2y-1)4、(a-b-2c)²5、(x+2y-3/2)(x-2y+3/2)6、已知,2x-y=1/3,xy=2,求2x^4y³-x³y^4的值. AB是圆X^2+Y^2-6X+4Y-7=0的直径,若A=(1,2)求B的座标 AB是圆x^2+y^@-6x+4y-7=0的直径.若A=(1,2),求B的坐标 把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)= 3(x-y)把(x-y)看作一个整体,化解:5(x-y)+2(x-y)-4(x-y)=3(x-y)²-4(x-y)+7(x-y)-6(x-y)²= {6(x-y)-7(x+y)=21 {2(x-y)-5(x+y)=-1 （x+y）/2- x-y/2=6 3(x+y)=4(x-y) x+y/3+x-y/2=6 4(x+y)-2(x-y)=40 {3(x+y)-4(x-y)=4 {x+y/2 + x-y/6=1 若(x-y)/(x+y)=3 则(x+2y)/(6x-7y)等于 x+y/2+x-y/3=6,4(x+y)-3(x-y)=-20 {(x+y)/2+(x-y)/3=6 4(x+y)-3(x-y)=-20 4(x+y)-3(x-y)=-20,2/x+y+3/x-y=6 x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 4ab(2x-y)+b(2x-y) 因式分解 已知x的平方-xy-2y的平方-x-7y-6=（x-2y+a）（x+y+b）,求ab的值 1.(a^2+ab+b^2)(a^2-ab+b^2)2.(7x-6y)^2+2(7x-6y)(7x+6y)+(7x+6y)^2化简求值1.(2x+y)(2x-y)+(x+y)^2-2(2x^2-xy)其中x=1,y=-1/42.已知x=6.61,y=-3.39.求(x-y)(x^2+3xy+y^2)-5xy*(x-y)的值