(X^2-2y) ^2
Những câu hỏi liên quan
Câu: Đẳng thức nào sau đây là đúng. *
4x^3y^2 – 8x^2y^3 = 4x^2.y(xy – 2y^2)
4x^3y^2 – 8x^2y^3 = 4x^2y^2(x – 2y)
4x^3y^2 – 8x^2y^3 = x^2y^2(x – 2y)
4x^3y^2 – 8x^2y^3 = 4x^2y^2(x – y)
ta có 4 x 3 y 2 – 8 x 2 y 3 = 4 x 2 y 2 . x – 4 x 2 y 2 . 2 y = 4 x 2 y 2 ( x – 2 y )
Vậy 4x3y2 – 8x2y3 = 4x2y2(x – 2y)
Đáp án cần chọn là: C
bấm đúng cho mik đi
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Rut gon:
A=(x-2)^2-(2x+1)^2
B=(x-2y)^2-(x-2y) .(2y+x)
C=(x+1)^3-(x-2)^3
D=(x-1)^2-2(x-1)(x+1)+(x+1)^2
E=(x+2y)^2+2(x+2y)(x-2y)+(2y-x)
G=(2x+1)^3-(2x-1)
Giai het ho minh nha! Minh dang can gap
\(A=\left(x-2\right)^2-\left(2x+1\right)^2=x^2-4x+4-4x^2-4x-1=-3x^2+3=-3\left(x^2-1\right)\)
\(=-3\left(x-1\right)\left(x+1\right)\)
\(B=\left(x-2y\right)^2-\left(x-2y\right)\left(x+2y\right)=\left(x-2y\right)\left(x-2y-x-2y\right)=-4y\left(x-2y\right)\)
\(C=\left(x+1\right)^3-\left(x-2\right)^3=\left(x^3+3x^2+3x+1\right)-\left(x^3-6x^2+12x-8\right)\)
\(=x^3+3x^2+3x+1-x^3+6x^2-12x+8=9x^2-9x+9=9\left(x^2-x+1\right)\)
\(D=\left(x-1\right)^2-2\left(x-1\right)\left(x+1\right)+\left(x+1\right)^2=\left(x-1-x-1\right)^2=-2^2=4\)
\(E=\left(x+2y\right)^2+2\left(x+2y\right)\left(x-2y\right)+2y-x=x^2+4xy+4y^2+2\left(x^2-4y^2\right)+2y-x\)
\(=x^2+4xy+4y^2+2x^2-8y^2+2y-x=3x^2-4y^2+4xy+2y-x\)
\(G=\left(2x+1\right)^3-\left(2x-1\right)=8x^3+12x^2+6x+1-2x+1=8x^3+12x^2+4x+2\)
\(=2\left(4x^3+6x^2+2x+1\right)=2\left(4x\left(x+1\right)^2+1\right)\)
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12 tháng 3 2022 lúc 21:56
(x^2y^2 - x^2y + 4xy + 2x - 4) + (-x^2y^2 - 6x^2y - xy + 2x+4) - (2x^2y^2 - 3xy +x - 4)
=
(x+y/2x-2y-x-y/2x+2y-2y^2/y^2-x^2):2y/x-y
Ta có: \(\left(\dfrac{x+y}{2x-2y}-\dfrac{x-y}{2x+2y}-\dfrac{2y^2}{y^2-x^2}\right):\dfrac{2y}{x-y}\)
\(=\dfrac{x^2+2xy+y^2-x^2+2xy-y^2+4y^2}{2\left(x-y\right)\left(x+y\right)}:\dfrac{2y}{x-y}\)
\(=\dfrac{4y^2+4xy}{2\left(x-y\right)\left(x+y\right)}\cdot\dfrac{x-y}{2y}\)
\(=\dfrac{4y\left(x+y\right)}{2\left(x+y\right)\cdot2y}\)
\(=1\)
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Tìm các đa thức P, Q và R biết a) P+(x^2-2xy+y^2)=5x^2+3xy-2y^2 b) Q-(xy+x^2-2y^2)=-x^2+y^2 c) (5x^2y-4xy^2+xy)-R=xy-x^2y+x^2y^2
rut gọn cac biểu thưc
a)(x-2y)(x+2y)+(x+2y)^2
b)(x^2-xy+y^2)(x^2+xy+y^2)
c)(x-2y+3z)(x+2y-3z)
cho 2 số thực `x,y` thỏa mãn `x>0,y>2,x`\(\ne\)`2y`. CMR: \(\left(\dfrac{x-y}{2y-x}-\dfrac{x^2+y^2+y-2}{x^2-xy-2y^2}\right)\left(2x^2+y+2\right):\dfrac{x^4+4x^2y^2+y^4-4}{x^2+y+xy+x}=\dfrac{x+1}{2y-x}\)
Đề bài sai, đề đúng thì phân thức đằng sau dấu chia phải là:
\(\dfrac{4x^4+4x^2y+y^2-4}{x^2+y+xy+x}\)
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g)(x+3y)(x-3y+2) h)(x+2y((x-2y+3) I)(x^2-xy+y^2)(x+y) J)(x^2-xy+y^2)(x+y) K)(5x-2y)(x^2-xy-1) L)(x^2y^2-xy+y)(x-y)
g: (x+3y)(x-3y+2)
=(x+3y)(x-3y)+2(x+3y)
=x^2-9y^2+2x+6y
h: (x+2y)(x-2y+3)
=(x+2y)(x-2y)+3(x+2y)
=x^2-4y^2+3x+6y
i: (x^2-xy+y^2)(x+y)
=x^3+x^2y-x^2y-xy^2+xy^2+y^3
=x^3+y^3
j: (x+y)(x^2-xy+y^2)=x^3+y^3
k: (5x-2y)(x^2-xy-1)
=5x*x^2-5x*xy-5x-2y*x^2+2y*xy+2y
=5x^3-5x^2y-5x-2x^2y+2xy^2+2y
=5x^3-7x^2y+2xy^2-5x+2y
l: (x^2y^2-xy+y)(x-y)
=x^3y^2-x^2y^3-x^2y^2+xy^2+xy-y^2
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Thực hiện phép tính :
a/ (x - 1)^2 - (4x + 3) (2 - x)
b/ (15x^3y^2 - 6x^2y^3) : 3x^2y^2 = (15x^3y^2 : 3x^2y^2) - (6x^2y^3 : 3x^2y^2) = 5x - 2y
c/\(\dfrac{x+7}{x-7}\) - \(\dfrac{x-7}{x+7}\) +\(\dfrac{4x^2}{x^2-49}\)
a/ (x-1)2-(4x+3)(2-x)=x2-2x+1-(8x-4x2+6-3x)
=x2-2x+1-8x+4x2-6+3x=5x2-7x-6
b/ (15x3y2 - 6x2y3) : 3x2y2 = 5x - 2y
c/ \(\dfrac{x+7}{x-7}-\dfrac{x-7}{x+7}+\dfrac{4x^2}{x^2-49}\)=\(\dfrac{\left(x+7\right)^2-\left(x-7\right)^2+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{x^2+14x+49-\left(x^2-14x+49\right)+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{28x+4x^2}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x\left(x+7\right)}{\left(x-7\right)\left(x+7\right)}\)=\(\dfrac{4x}{x-7}\)
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x^2y^2+(x-2)^2+(2y-2)^2-2xy(x+2y-4)=5