1.过圆X^2+Y^2+6X-2Y-15=0的圆心的直线是?A.X+2Y-1=0B.X+2Y+1=0C.X-2Y-1=0D.X-2Y+1=02.直线X-Y-C=0与X^2+Y^2=4有一个交点,则C的值为多少?A.2B.正负2C.-2D.正负2√2

【2(x-y)(x-y)(x-y)-8(x-y)(x-y)(x+y)+6y(x-y)(x-y)]/2(x-y)(x-y) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 化简y(x+y)+(x+y)(x-y)-x^2 计算:(x-y)^2*(y-x)^2*(x-y)^6 6(x+y)2-2(x-y)(x+y)因式分解 (x+y)(x-y)-(x-y)^2如题 (x+y)(x-y)-(x-y)^2 1.（（y+2x)(-2x+y)+4(x+2y)^2)/3y 2.（2(x-y)^3-8(x-y）^2(x+y)+6y(x-y)^2）/2（x-y)^2 1.过圆X^2+Y^2+6X-2Y-15=0的圆心的直线是?A.X+2Y-1=0B.X+2Y+1=0C.X-2Y-1=0D.X-2Y+1=02.直线X-Y-C=0与X^2+Y^2=4有一个交点,则C的值为多少?A.2B.正负2C.-2D.正负2√2 (x+y)^2+6(x+y)+9 因式分解x(x+y)(x-y)-x(x+y)^2 [2(x-y)^5-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2[2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2]÷2(x-y)^2 3y/x*x-y*y+x/x*x-2xy+y*y+6y*y/x*x*x-x*x*y-xy*y+y*y*y等于多少? 因式分解3x^2(x-y)+6x(y-x) 【2(x-y)^3-8(x-y)^2(x+y)+6y(x-y)^2】/2(x-y)^2= [(x-y)^2-(x+2y)(x-2y)]/y 计算:y-x分之x+y+x-y分之y-y-x分之2x-y 1.(x-2y)(x+2y)-(x平方+y)(x平方-y) 2.(2x-y)(y+2x)-(2y+x)(2y-x)3.已知：x+y=6,x平方-y平方=48,求x,y的值4.x平方-2x分之x+2 -- x平方-4x+4分之x-1 1.（x+2)^2-(x+y)^32.(x-y)^2-(x-y)^33.(x-y)^2-(y-x)^3