y=2340/x+13/18x,x∈[50,100].x取何值时y最小?y=2340/x+(13/18)*x

y=2340/x+13/18x,x∈[50,100].x取何值时y最小?y=2340/x+(13/18)*x 用递归法求y=x-(x*x*x/3!)+(x*x*x*x*x/5!)-(x*x*x*x*x*x*x/7!)+. y=|-x.x+4x+5| y-x=x-5 （x+y-5)*（x+y-5)+（x-y+3)=0 x*x-y*y 已知:3x-5y=0,求x/y,x-y/y,x-y/x x+x+x+x+y=40 x+y= 13x=y= x+y=5; x^y+y^x=17 (x+2y)(x-2y)-(2x-y)的平方+(3x-y)(2x-5y)其中x=-1 y=13分之1 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 若(X×X+Y×Y)(X×X+Y×Y-5)=36,则X×X+Y×Y＝ y=x(x (X-Y)(X+Y)=5 能解么 5x-4y(y-x)=? x-y+5x-4x= ?x-y+5x-4x= ? x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 x:18=y:13 x-y=50, 化简 x / y(x+y) - y / x(x+y) =