15题,x+y=2 求a

15题,x+y=2 求a 已知x+y=a,2x-y=-2a,求[（x/y-y/x)/(x+y)-x(1/x-1/y)]/[(x+1)/y]的值 已知方程组 2x+y=3a x-2y=a 求x/y 已知x+y=a,x-y=b.求:x^2+y^2;xy x+y=a,x-y=b.求2x-3y等于 设集合A={(x,y)|(y-3)/(x-2)=a+1},B={(x,y)|(a^2-1)x+(a-1)y=15}若A∩B=空集 求实数a的值 求详解 求微分方程通解 y'' + a^2*y = e^x A={x|y=根号-x2-2x+15},B={y|y=-x2-2x+a},(1)若A包含B,求a的范围 a/b = 1-x/y 求b/a(a)x/(y-x)(b)y/x-1(c)y/(x-y)(d)x/y + 1(e)y/(y-x)第2题(3y-1)(2y+k) = ay的平方+by-5求a+b等于多少 x^2+y^2=15,x+y=7,x＞y,求x-y x+y+z=12 x-y+z=2 x-z+y+a=90 x+y+a+z=100,求x y z a 方程组:3(x+y)-a(x-y)=16 2(x+y)+b(x-y)=15,求初二学生会的具体步骤. 根号(x-a)+根号(y+a-2)=(x+y)÷2,求x+y的值,求思路! A=(x-y)*100;B=(x+y)/2;x=?/y=?/求X及Y解答公式 已知非空集A={(x,y)|(a^2-1)x+(a-1)y=15},B={(x,y)|y=(5-3a)x-2a},若A交B=空集,求实属a的值 已知集合A={y|y=x2+2x－3,x∈R},B={y|y=－x2+2x+15,x∈R},求A∩B知集合A={y|y=x2+2x－3,x∈R},B={y|y=－x2+2x+15,x∈R},求A∩B 已知a^x=2,a^y=3,求a^x+y A:{(x,y)|y=x方+2x},B:{(x,y)|y=x+a},A交B的真子集为空集,求a的范围