若圆C:x^2+y^2-x+3y-27/2=0关于直线l:a/2x+4y+30=0对称,则直线l的倾斜角是多少?A π/6B 5π/6C π/3D 2π/3选项是 A 96B 36C 12D 6

a(x-y)(x+y)-b(y-x)(x+y)-c(x-y)^2(y+x)提取公因式 x(x-y)2-(y-x)3 3(x+y)-4(x-y)=11,2(x-y)+5(x+y)=27 [2/3x-2/x+y(x+y/3x-x-y)]/x-y/x 化简：{2/3x-2/(x+y)[(x+y)/3x-x-y]}/(x+y)/x 计算2/3x-2/x+y(x+y/3x-x-y)/x-y/x 化简3x-2/(x+y)[(x+y)/3x-x-y]÷(x-y)/x a/x-y,b/3y-3x,c/x^2-2xy+y^2通分 计算：x+2y/x-y+2x/y-x-3y/x-y 化简:(x-3y)(x+y)-(x-2y)(x+2y)-(x-y)平方 [(3x+y)(x-y)-(2x+3y)(x-y)]*(x-y) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 2X(2X-3Y)-3Y(X+Y) (-2x y)^2-(3y-x)(-x-3y) （x+2y)^2-(x+y)(3x-y) 计算(x+y)(x+y)^2(-x-y)^3 化简:5(x-y)+2(x+y)-3(x-y)