y=x(30-x)/2怎样化简

y=x(30-x)/2怎样化简 4x - 2y + 5x怎样化简? 2分之x-y=1怎样化简 怎样化简:4x^3(-y^3)^2-3x*(-x)^2*(-y^2)^3 化简求值：2(x+y)(x-2y)-2x(x+y),其中x、y满足x^2+y^2-2x+4y=-5 x³-y³怎样化简 请问方程x^2-xy+y^2+x-y-1=0是哪种曲线?怎样化简?怎么求对称轴? 怎样化简x的方＋4y的方-2x-12y＋6=0 2(2X-3Y)-(3X 2Y 1)怎样化简 怎样化简：2x²-2y²+3xy-5y²+x² (x/x+y-x/y-x-2xy/x.x-y.y)/(1/x-1/y) 分式化简 化简求值:[2x的平方-(x+y)(x-y)][(-x-y)(y-x)+2y的平方],其中x=1,y=2 化简求值:[(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y,其中x=二分之一,y=2 化简求值:[(x+y)(x-y)-(x-y)²+2y(x-y)]÷4y,其中x=二分之一,y=2 怎样求导y=x^(1/x) x-y/x-x+y/y-(x+y)(x-y)/y² y/x=2 X-10=7X(y-70)和2X+30=y+15怎样解方程 化简求值 [(x-y^2)+(x+y)(x-y)]÷2x.[(x-y^2)+(x+y)(x-y)]÷2x.化简求值 x=3 y=1.5