x2+y2=25 x+y=7 x>y 求x-y=?
已知:x2+y2=25,x+y=7,求x-y.
已知x2+y2=25,x+y=7,且x>y,求x-y.
我做对了吗.x2(x-y)+y2(y-x)= x2(x-y)-y2(x-y)=x2-y2=(x+y)(x-y)
0.5ln(x2+y2)=arctan(y/x),(x≠0,x≠y),求y’.
正整数x,y满足x2-y2=2xy,求x-y/x+y的值
整数x,y满足x2-y2=2xy,求x-y/x+y的值
x2-x-y2-y 解法:=(x2-y2)-(x+y) =(x+y)(x-y)-(x+y) =(x+y)(x-y-1)
已知x-y+1,X2+Y2=25 求(x+y)2和x2-xy+y2的值
已知[(x2+y2)-(x-y)2+2y(x-y)]÷4y=1,求4x/4x2-4y2-1/2x+y的值,
已知实数x、y满足2x2-7xy+3y2=0,求x:y
已知X2+Y2+8X+6Y+25=0 求代数式X2++XY+4Y2分之X2-4Y2 减X+2Y分之X的值
X2+Y2+8X+6Y+25=0 求代数式(x2-4y2/x2+4xy+4y2)-x/x+2y