圆C:x^2+y^2-2x+4y-15=0 上有一点(x,y) 求2x+y的最大值和最小值圆C:x^2+y^2-2x+4y-15=0上有一点(x,y)求2x+y的最大值和最小值答案是10,-10 感恩

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 2（x+y)-3(x-y)=3 ,4(x+y)+3(x-y)=15 (x-y) (x-2y)+(x+2y) (x-3y)-2(x-3y) (x-4y)= 如果A={（x,y）|x,y+2>0},B={（x,y）|2x+3y-6>0},C={（x,y）|x-4 (x-4y)(2x+y)= 圆C:x^2+y^2-2x+4y-15=0 上有一点(x,y) 求2x+y的最大值和最小值圆C:x^2+y^2-2x+4y-15=0上有一点(x,y)求2x+y的最大值和最小值答案是10,-10 感恩 a(x-y)(x+y)-b(y-x)(x+y)-c(x-y)^2(y+x)提取公因式 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? 1、(x+y)-(x+y)^32、x(x-y)-y(y-x)3、(a-b)^2-4b+4a4、a^n+1+a^n+a^n-15、x(x+y)(x-y)-x(x+y)^26、已知a+c-7=0,求(a+b)^2-2a(b-c)-2b(b-c)+(c-b)^2的值7、x^2-8y^2(x^2-2y^2) [(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y (x+y)^2(x-y)^2(x^4+x^2y^2+y^4)=? x^2+y^2=15,x+y=7,x＞y,求x-y y'=（y/x）^2+y/x+4微分方程 3(x+y)+2(x-y)=36 4(x+y)-5(x-y)=2 （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 x*x+2x+y*y-4y+5=0 x= y=