化简求值3x-2y-[-4x (y 3x)]-(2x 3y)

原式=16x²-24xy+9y²-25x²-10xy-y²+9x²-6xy-8y²=-40xy=-40*1/3*6=-80

原式=9x²+12xy+4y²-18x²+8y²+9x²-12xy+4y²=16y²=16×4=64

（2X+3Y）²-（2X+Y）（2X-Y）=4X²+12XY+9Y²-（4X²-Y²）=4X²+12XY+9Y²-4X²

不用化了因为x=8,y=-8所以x+y=0式子中有个x+y所以整个式子的结果是0如果不懂,请追问,祝学习愉快!再问：步骤再答：x+y=0所以(x+y)(x-2y)(x²-4y²)=

感觉你题目写错了式子应该是这样[(y-2x)(-2x-y)-4(2x-y)^2]÷3y我就按我写的式子做了原式=[(2x-y)(2x+y)-2(2x-y)]÷3y=(2x-y)(2x+y-2)÷3y当

[(y-2x)(-2x-y)-4(x-2y)²]÷3y=[4x^2-y^2-4x^2+16xy-16y^2]/3y=[16xy-17y^2]/3y=16x/3-17y/3再问：a²

原式可化为[(15x²+16xy+4y²)+(x²-4y²)]/4x=(16x²+16xy)/4x=4x+4y代入得4×2+4×3=20

原式=3y^2+xy-6xy-2x^2+2x^2-3y^2=【3y^2-3y^2】-【2x^2-2x^2】+【xy-6xy】=-5xy∵x=3/1y=-3∴原式=-5×1/3×-3=5

8x^2-20xy+5x^2-16x^2+10xy-3x^2-10xyx=1,y=3-3-30=-33

(7x-2y)(3x-2y-1)-(4x+3y)(9x+6y)=21x^2-14xy-7x-6xy+4y^2+2y-36x^2-24xy-27xy-18y^2=-15x^2-70xy-7x-14y^2

化简求值2(x-zy)^2-4(x-2y)+(x-2y)^2-3(x-2y),其中x=-1,y=1/2.2（x+2y）²-4(x-2y)+(x+2y)²-3(x-2y)=3(x+2

原式=(9x^2-3xy+1/4y^2+3xy-1/4y^2)÷(4x^2+4xy+u^2-4xy-y^2)=9x^2÷4x^2=9/4

解(x²-4y²)/(4x²-8xy)=(x-2y)(x+2y)/4x(x-2y)=(x+2y)/4x=(2-3×2)/(4×2)=-4/8=-1/2

:2(x-2y)^2-4(x-2y)+(x-2y)^2-3(x-2y)=2(x-2y)^2+（x-2y)^2-4(x-2y)-3(x-2y)=3（x-2y)^2-7(x-2y)=（x-2y）（3（x-

原式=4x-2y-（-2x+2y+2x+y）-4x=4x-2y+2x-2y-2x-y-4x=-5y，当x=0，y=-3时，原式=-5×（-3）=15．

冷风你数学退步了啊!严肃批评!原式=[(-1/2×-1^3×1/2^4)^3+(-1/6×-1×1/2^2)^2×3×-2×1/2^2]÷（-1/2×-2×1/2^2)^3=[(-1/2×-1×1/1

-3(2x-y)-｛7x-〔6x+2x-(10x-8y)〕-x-2(3x-4y)｝=-6x+3y-｛7x-〔8x-10x+8y)〕-x-6x+8y｝=-6x+3y-｛7x-〔-2x+8y)〕-7x+8

(x+y)-(2x+1/2y)-(3x+1/6y)-(4x+1/12y)-(5x+1/20y)-.-(10x+1/90y)=x+y-2x-1/2y--3x-1/6y-4x-1/12y-5x-1/20y

原式=[(5x²+8xy-4y²)-(9x²-4y²)]÷4x=(-4x²+8xy)÷4x=-x+2y当x=2,y=-1时原式=-2-2=-4

[4(x^2+y)(x^2-y)-(2x^2-y)^2]÷y=[4(x^4-y²)-(4x^4-4x²y+y²)]÷y=[4x^4-4y²-4x^4+4x