数学题{3X-2Y=10 5X+3Y=80

数学题{3X-2Y=10 5X+3Y=80 数学题……555{(3x+y)(3x-y)-(x-5y)(5x-y)-(x-2y)²÷(-4x),x=-2.y 数学题（2x+y)：（x+2y)=2：3,x：y得多少 已知x-y/x+y=3,求代数式5(x-y)/x+y-x+y/2(x-y) 数学题3x+2y=10 2x-4y=-2 (4x-2y-z)-{5x[8y-2y-(x+y)]-x+(3y-10z)]=? kuai 数学题--已知x+1/2=y+3/4=x+y/5,则3x+2y+1/x+2y+3= 数学题--已知x+1/2=y+3/4=x+y/5,则3x+2y+1/2x-y+3=? 一道初一下学期数学题二元一次方程组{[2x+y]/4-[5(x-2y)]/3=6 {[3(2x+y)]/4-[x-2y] 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 数学题化简再求值（1/x-y+1/x+y）÷x^2 y^2/x^2-y^2,其中x=3,y=-√2 先化简再求值(x-y)(x+y)-(x-2y) 的完全平方+x(3x-5y)-(x-y)(x-2y),其中x=1/2 y