x+y=60 2%x+5%y=2.4怎么解

x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x+y=60 2%x+5%y=2.4怎么解 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? X+y=15 2x-y=5y-x怎么解 二元二次方程(x+y)(x-2y)=-5,(x-y)(x+2y)=7 怎么解 二元一次方程(x+y)/2+(x-y)/3=6,4(x+y)-5(x-y)=2怎么算 y-x/7-x+y/6=1/2 5(x+y)-2(y-x)=1怎么解答 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) x+x+x+y+y=6.4 y+y+y+x+x=7.1 怎么算? y/(x+y)-x/(x-y)=?怎么算? {2X=5(X+Y)3X-10(X+Y)=2怎么解? 由X/Y=2Y/X-Y 怎么解得x=2y? 3x*5y+2x*6y=2.7*(3x+2x)怎么解 X^2Y+Y=X^怎么转换成X^=1-Y分之Y 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. ｛x/60+y/80=10,x/60+y/40=15、｛2x/3+3y/4=1/5,5x/6-5y/2=2、｛5/2(x+y）=1200,10/3（x+y）=1200｛4x+5y=98,5y-4x=2、｛x/3+y/4=54/60,y/4+x/5=42/60怎么解?{40-y=x-4 40-y=y-x 3x+2=y 5x+4=y 7x+6=y 9x+8=y 11x=y怎么解 2y''+5y'=x的通解怎么算