1-0.3(y-2)=(x+1)/5和(y-3)/4=(4x+9)/20-1.
(1)﹛2x-y=5 (2) 4x-y=1 (3)5x+y=2 7x-3y=20 y=2x+3 x-3y=4 (4)3x
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
化简[(3x+4y)^2-(2x+y)(2x-y)+(-x+y)(5x-y)]除以-2y,其中x=-1,y=1
已知X,Y,满足(X+3Y)(X-3Y)=-10(Y^2-6/5)和2X(Y-1)+4(1/2X-1)=0
利用关系式判断,y和x成什么比例 8x=y( ) x/4=y( ) y/8=5/x( ) 1/x=y( )
求定义域和值域(1)y=-2x(2)y=x+3(3)y=-2/x(4)y=x²+2x+1(5)y=-x
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
(1){x+2y=0,3x+4y=6(2){5x+6y=16,7x-9y=5(3){9x-11y+1=0,4x-5y-3
1.解下面方程组(1)2x-4y=63x+2y=17(2)3x+5y=53x-4y=23(3)3x-y=05x-5y=-
解方程组3(x+y)-4(x-y)=4和(x+y)/2+(x-y)/6=1
实数x,y满足x^2+y^2+2x-4y+1=0,求下列各式的最大值和最小值 (1)y/x(2)2x+y(3)y/x+4
已知X和Y满足3X+4Y=2,X-Y-1/7