(3-Y)(9+3Y +Y2)

(3-Y)(9+3Y +Y2) 3y2 (2y 若-3＜y2化简：|y-2|-|3y+9| 计算(x+y/x-y + 4xy/y2-x2)(x2-9y2)/（x2+2xy-3y2） 先化简,再求值：9y+6y2-3（y-2/3y2）,其中y=-2 已知9-6y-4y2=7,求2y2+3y+7的值.（y2代表y的平方）急! x2-4y2-3xy+y+x (x2-y2)-4(2x2-3y) 已知y2-3y+5的值为9,求-3y2+9y+42的值 (3y2-y)2=3(3y2-y)-2答案和解题过程 一元二次方程 x+y=0.5 x+3y=1.2 求3x2 +12xy +9y2 x2+2xy+y2-9=0 (x-y)2-3(x-y)+2=0 解方程3/y-1+5y-2/y2-y=6/y 先阅读下面例题的解题过程,再解决后面的题目．例已知9-6y-4y2=7,求2y2+3y+7的值．解：由9-6y-4y2=7,得-6y-4y2=7-9,即6y+4y2=2,所以2y2+3y=1,所以2y2+3y+7=8． y2+3y=9求Y=?(Y2是Y的平方)我要详解一步步的说明谢啦 因式分解3x2+xy-y2+x+9y-43X^2+XY-Y^2+X+9Y-4 因式分解 2x2+xy-y2-4x+5y-6 x2-y2+a2-b2+2ax+2by 3x2+5xy-2y2+x+9y-4 b4-2b2-82x2+xy-y2-4x+5y-6x2-y2+a2-b2+2ax+2by3x2+5xy-2y2+x+9y-4b4-2b2-8 解方程组 ｛3x2-y2=8 {4x2+12xy+9y2=1 {x2+2xy+y2-4=0 x2+xy+y2=4 4x2-9y2=0 x2-2xy+y2-1=0还有{x2+y2=4xy-y2+4=0x2-----x的平方 y2------y的平方 还有{2x-3y=12x2-3xy+y2-4x+3y-3=0