10y-10x=1500/30 y*(1-20%)*20-20x=1200/30的一元二次方程组怎么解呢?

{6/x+y+10/x-y=30 6/x+y-10/x-y=-1 (x+y)/6+(x-y)/10=1,(x+y)/6-(x-y)/10=5 x+(9-8-y)=10 y+y-(9-8-y)=2 x-y=xx-9.9x xy=11y-1 y=? x=? x+y-xy=?x+(9-8-y)=10y+y-(9-8-y)=2x-y=xx-9.9xxy=11y-1 y=?x=?x+y-xy=? 方程组：第一题（5+1）x=5y 第二题x-y/3=x+y/2 4y-4x=30+10 2x-3y=7（5+1）x=5y x-y/3=x+y/2 4y-4x=30+10 2x-5y=7 上面那个题目错的 y-x=1 10x+y> 10x+y30 10x+y 已知y/x=9/10则(1-y/x)[x/(y-x)]? (x+y+z)÷10=x+1.1 y+x=z-80+y-1 z-y=8x+y+8 x+z÷y=? {4x-3y-10=0 3x-2y=0,{3x-4(x-y)=2 2x-3y=1,{2(x+y)-(x-y)=3 (x+y)-2(x-y)=1 25（x+y)^2+10(y-x)+1=?因式分解 25(x-y)^2+10(y-x)+1= y=ln(1+x),求y^10(x)? 解方程组x+y/6+x-y/10=3,x+y/6+y-x/10=-1x+y/6+x-y/10=3 ①x+y/6+y-x/10=-1 ② x+y=20,x-y=10,y= x-y/7 - x+y/10 =1/2 2(x-y)-5(x+y)=3修改、、、、（x-y)/7-(x+y)/10=1/2 2(x-y)-5(x+y)=3 1.5（x+y）+3（x-y）=27（x+y）-3（x-y）=-62.x-y/7 - x+y/10 =1/22(x-y)-5(x+y)=3所谓细节决定成败, 10X+Y+1/3Z=10Y+X 10X+Y+2/3Z=100X+Y 解二元一次方程(1)2x+y=10,x+2y=8.（2）x+y=18,30%x+70%y=18×50（3）x+y=460,43x=44y=20000 用加减法解方程组:{(x+y)/6+(x-y)/10=3 (x+y)/6+(y-x)/10=-1