X-4y=-1 2x+y=16怎么做

X-4y=-1 2x+y=16怎么做 x+y+2y-1=44怎么做 (2X 3Y=16 X 4Y=12)这个方程怎么做 推倒公式:(x+y)(x*x-3x+y*y)=x*x*x+y*y*y怎么做. 2x+3y=-1,4x-9y=8怎么做?2x+3y=-1,4x-9y=8 [4y（2x-y)-2x(2x-y)]÷（2x-y)怎么做 4x^2+2xy-2y^2+4x+7y-3分解因式:4X^2+2XY-2Y^2+4X+7Y-3=4X^2+(2XY+4X)-(2Y^2-7Y+3)=4X^2+(2Y+4)X-(2Y-1)(Y-3)=(2X+2Y-1)(2X-Y+3) 其中=4X^2+(2Y+4)X-(2Y-1)(Y-3)之后该怎么做? 4x方y/(x-2y)(x+2y)怎么算[x方/x-2y]-4x方y/(x-2y)(x+2y)=? {x+y+z=26,x-y=1,2x+z-y=18怎么做? 求dy/dx, x^2y^2-4y=1这题怎么做? (2x-y+1)(2x+y+1)怎么做? (2x+y+1)(2x+y-10)怎么做 (X-Y)^2-4(X-Y)+3怎么做, 已知x+y=-1求：x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4的值.x^4+5x^3y+x^2y+8x^2y^2+xy^2+5xy^3+y^4 ①=(x+y)(x^3+4x^2y+xy+4xy^2+y^3) ②从第①步到第②步是怎么做的? matlab画二元函数图像z = (x/(x+y) + 1.96*1.96/(2*(x+y)) - 1.96 * ((x/(x+y)*(1-x/(x+y))+1.96*1.96/(4*(x+y)))/(x+y))^0.5)/(1+1.96*1.96/(x+y))该怎么画 微分方程 y'=2y-x/2x-y 怎么做. 要过程 . Y=X^/2-2/X^求导怎么做? {2x+3y=4 5x-5y=-3{2x+3y=4 5x-5y=-3怎么做，