Y-X=20 0.4X 0.8Y=35怎样解
已知X+Y=-4,怎样求二分之一X+Y-4X-Y+3X+Y-二分之三X+Y+X-Y的值
解方程 {x+y=20 x-y=12
怎样解三元一次方程组(1)x+y-z=11,y+z-x-5,z+x-y=1
解方程组(x+y)(x-2y)=-5 (x-y)(x+2y)=7
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
0.5x+0.7y=35,x+0.4y=40.求x=?,y=?
x*y'*sin(y/x)-y*sin(y/x)+x=0 求微分方程的解
解方程x*x+xy=y+y*y
解方程组 x=3y-6 0.8(x+y)=x+y-13.6
解方程组x+y+√(x+y)=20;x²+y²=136