四年级数学已知x-y=12.问5x-5y=?
初二数学已知(x-y):y=2:3,求(2x+5y):(3x-y)的值
已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y)
已知:4x = 5y,求(x+y) :y
已知x/5=y/3,则(x/x+y)+(y/x-y)-(yxy/xxx-yxy)
已知3X²-2y=4,-X²-3y=3,问:①4X²+y=( ) ②2X²-5y
问一条数学题:已知实数x、y满足√(2x-3y-1) + |x-2y+2|=0,求2x- 4/5y的值
已知x*x+4x+y*y-2y+5=0,则x*x+y*y=?
已知x+y=-5,x*x+y*y=19求xy和(x-y)*(x-y)的值
问:已知y=根号下5-x加根号下x-5+3,求x+2y的平方根?
已知x,y满足约束条件x-y+5>=0 x+y>=0 X
已知x=1/3,y=-1/2,求代数式x-(x+y)+(x+2y)-(x+3y)+(x+4y)-(x+5y)+...-(
已知x²+y²+5=2x+4y,求【2x²-(x-y)(x-y)】【(x+y-1)(x-y