设甲速度x,30秒相遇就是 30(x+y)=400 80秒乙相遇就是 80y-30x=400 x=20/3,y=80/1
甲、乙两人在200米的环形跑道上练习径走,当他们从某处同时出发X=(2-Y)/3背向行走时,每30秒相遇一次;同向行走时
x-80=y,(1-25%)x+30=(1+20%)y问x=?y=?
4x-2y-6y*-y-3x+5y* *=2 就是平方
(1)x+y=420,30%x+40%y=160×80% (2)x-y/7-x+y/6=1/2,2(x-y)-5(x+y
设变量xy满足 x+y-3 x-y+1 3x-y+5 z=x+y/x
解方程组:(0.2x+0.1y)/2- (4x-y)/10=(x-y)/5+ (3x+0.5y)/30 (3x+2y-1
x+y=20-6 3x+y=30
设x>1,y>0,若x^y+x^-y=2根号2,则x^y-x^-y等于
|x|+|y|=30 2|x|-3|y|=20 求x,y
设变量x,y满足约束条件x-y>=-1,x+y>=1,3x-y
设x,y满足约束条件x>=0 y>=x 4x+3y
设y=x(x-1)(x-2)(x-3)——(x-n),则y^(n+1)=?