y=3x+2 y=5x+4 y=7x+6 y=8x=7 y=11x 求xy=多少
y=3x+2 y=5x+4 y=7x+6 y=8x=7 y=11x 求xy=多少
已知x*x-4xy+4y*y=0 求[2x(x+y)-y(x+y)]/(4x*x-4xy+y*y)的值?
若(x*x+y*y)(x*x+y*y)-4x*x*y*y=0,求代数式(x*x+5xy+y*y)/(x*x+2xy+y*
已知xy=-2,x-y=3,求(x+y)(x-y)-y^2+(x-y)^2-(6x^2y-2xy^2)÷2y
已知x的平方+y的平方-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知3x^2+xy-2y^2=0,求{(x+y)/(x-y)+4xy/(y^2-x^2)}/{(x+3y)*(x-y)}
已知x,y>0 2x+y+3=xy 求5x+4y最小值
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
xy=-2,x+y=3,求代数式(4xy+12y)+[7x-(3xy+4y-x)]
x+y=8,xy=-2,求(5xy+4x+7y)+(6x-3xy)-(4xy-3y)的值
已知x=3y,试求(x-y)^2+2xy-y^2/x^2+7xy+y^2