已知4x²y-3y²=7,3x²y+4y²=19,求11x²y-2y&

已知4x²y-3y²=7,3x²y+4y²=19,求11x²y-2y& 已知x/y=2,求2x(x+y)-y(x+y)/4x²-4xy+y² 已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y 已知2x-y=10,求式子[(x^2+y^2)-(x-y)^2+2y(x-y)]/4y (4xy-2y²)/4 已知x²+4y+y²—6y+13=0,求2x+3y的值 已知X²+3XY-4Y²=0（Y≠0）求X-Y/X+Y 已知:x+y=-½,x-y=-7/2,求x-2(1/4x-1/3y²)+(-3/2x+1/3y
已知x,y满足x²+y²-4x+6y+13=0则(3x+y)²-(3x+y)(3x-y)的 已知x²+y²-2x+4y+5=0,求x+y 已知x² +y²+5/4=2x+y,求y-x的值 已知|3x+2y-4|+4(5x+7y-3)²=0,求x,y的值. 已知x²+4x+y-2y+5=0求x+2y