12x+20y=20x+12y
解方程 {x+y=20 x-y=12
(x*x+y*y)(x*x+y*y)-(x*x+y*y)=12 求x*x+y*y等于多少
化简(x+y)-(2x+y/2)-(3x+y/6)-(4x+y/12)-(5x+y/20)-……-(10x+y/90)
解方程组 x+2y=1.5,12(x+y)+15y=20
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
化简求值:(x+y)-(2x+1/2y)-(3x+1/6y)-(4x+1/12y)-(5x+1/20y)-.(10x+1
12(x+y)平方/20(x+y)(x+2y)约分
这个方程怎么解2x=8y 20x+12y=2300x=?y=?
20(x+y)=12(y+z)=15(z+x),且xyz不等于零,求x:y:z=
已知20(x+2y)=15(y+3Z)=12(z+5x),则x:y