已知:x-y=4 ,(x²+y²)=49 ,求x²+y²的值
已知非零有理数x,y满足x²-4xy+4y²=0,求x-y/x+y-y-x/x+y的值.
已知2x-y=10,求代数式[(x²+y²)-(x-y)²+2y(x-y)]÷4y的值?
已知x-y=4,x²-y²=20,求x-y的值
已知x² +y²+5/4=2x+y,求y-x的值
已知x²+4y²-6x+8y+13=0,求x-y/x+y的值.
已知:x-y=4 ,(x²+y²)=49 ,求x²+y²的值
已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y²
已知x²+y²-8x+6y+25=0,求(x-y+4xy/x-y)(x+y-4xy/x+y)
已知2x-y=10,求[(x²+y²)-(x-y)²+2y(x-y)]/4y的值
已知2x-y=10,求代数式[x²+y²-(x-y)²+2y(x-y)]÷4y的值
已知x²+y²=25,x+y=7,求x-y的值.
已知x²-y²=12,x+y=6,求x,y的值