\(\dfrac{1}{3}\)x+2y).(\(\dfrac{1}{9}\)x...">
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a: \(\left(\dfrac{1}{3}x+2y\right)\left(\dfrac{1}{9}x^2-\dfrac{2}{3}xy+4y^2\right)=\dfrac{1}{27}x^3+8y^3\)

b: \(\left(x^2-\dfrac{1}{3}\right)\left(x^4+\dfrac{1}{3}x^2+\dfrac{1}{9}\right)=x^6-\dfrac{1}{27}\)

c: \(\left(y-5\right)\left(y^2+5y+25\right)=y^3-125\)

3 tháng 9 2018

pạn ơi pạn đã lm đk chưa? nếu lm đk oy cho mk xem cách lm bài 2 nhé. cảm ơn pạn nhìu lắm

29 tháng 1 2019

a) \(\left(6x^3y^2-4x^2y^3-10x^2y^2\right):2xy\)

=\(\left(6x^3y^2:2xy\right)-\left(4x^2y^3:2xy\right)-\left(10x^2y^2:2xy\right)\)

\(=3x^2y-2xy^2-5xy\)

b) \(\dfrac{2y}{x-2}+\dfrac{5y}{x-2}\)

=\(\dfrac{2y+5y}{x-2}\)

=\(\dfrac{7y}{x-2}\)

c)\(\dfrac{xy}{3x-y}+\dfrac{3x^2}{y-3x}\)

\(=\dfrac{xy}{3x-y}-\dfrac{3x^2}{3x-y}\)

=\(\dfrac{x\left(y-3x\right)}{3x-y}\)

=\(\dfrac{-x\left(3x-y\right)}{3x-y}\)

=-x

d)\(\dfrac{x-1}{6x+12}.\dfrac{x+2}{x-1}\)

=\(\dfrac{\left(x-1\right)\left(x+2\right)}{6\left(x+2\right)\left(x-1\right)}\)

=\(\dfrac{1}{6}\)

23 tháng 7 2018

a ) \(\left(5x+2y\right)^2=25x^2+20xy+4y^2\)

b ) \(\left(-3x+2\right)^2=9x^2-12x+4\)

c ) \(\left(\dfrac{2}{3}x+\dfrac{1}{3}y\right)^2=\dfrac{4}{9}x^2+\dfrac{4}{9}xy+\dfrac{1}{9}y^2\)

d ) \(\left(2x-\dfrac{5}{2}y\right)^2=4x^2-10xy+\dfrac{25}{4}y^2\)

e ) \(\left(x+\dfrac{4}{3}y^2\right)^2=x^2+\dfrac{8}{3}xy^2+\dfrac{16}{9}y^4\)

f ) \(\left(2x^2+\dfrac{5}{3}y\right)^2=4x^4+\dfrac{20}{3}x^2y+\dfrac{25}{9}y^2\)

21 tháng 12 2017

câu a hình như sai đề rồi bạn ạ

27 tháng 6 2018

Mk xin lỗi nha, câu c sai đề

c) (x+6)4 + (x+8)4 = 272

21 tháng 1 2018

Ai lm giúp mk vs câu nào cũng được. Ai làm xong sớm nhất sẽ được tick

21 tháng 8 2017

\(e,\)

\(\left(\dfrac{1}{3}a^3b+\dfrac{1}{3}a^2b^2-\dfrac{1}{4}ab^3\right):5ab\)

\(=\dfrac{1}{15}a^2+\dfrac{1}{15}ab-\dfrac{1}{20}b^2\)

\(f,\)

\(\left(-\dfrac{2}{3}x^5y^2+\dfrac{3}{4}x^4y^3-\dfrac{4}{5}x^3y^4\right):6x^2y^2\)

\(=-\dfrac{1}{9}x^3+\dfrac{1}{8}x^2y-\dfrac{2}{15}xy^2\)

\(g,\)

\(\left(\dfrac{3}{4}a^6b^3+\dfrac{6}{5}a^3b^4-\dfrac{5}{10}ab^5\right):\left(\dfrac{3}{5}ab^3\right)\)

\(=\dfrac{5}{4}a^5+2a^2b-\dfrac{5}{6}b^2\)

21 tháng 8 2017

cam on

15 tháng 7 2018

a) \(4.\left(x-1\right)^2-9=0\)

\(\Rightarrow4.\left(x-1\right)^2=9\)

\(\Rightarrow\left(x-1\right)^2=9:4=\dfrac{9}{4}=\left(\pm\dfrac{3}{2}\right)^2\)

\(\Rightarrow x-1=\pm\dfrac{3}{2}\)

\(\Rightarrow\left[{}\begin{matrix}x-1=\dfrac{3}{2}\\x-1=\dfrac{-3}{2}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=\dfrac{-1}{2}\end{matrix}\right.\)

vậy\(\left[{}\begin{matrix}x=\dfrac{5}{2}\\x=\dfrac{-1}{2}\end{matrix}\right.\)

b) \(\dfrac{1}{4}-9.\left(x-1\right)^2=0\)

\(\Rightarrow9.\left(x-1\right)^2=\dfrac{1}{4}\)

\(\Rightarrow\left(x-1^2\right)=\dfrac{1}{36}=(\pm\dfrac{1}{6})^2\)

\(\Rightarrow x-1=\pm\dfrac{1}{6}\)

\(\Rightarrow\left[{}\begin{matrix}x-1=\dfrac{1}{6}\\x-1=\dfrac{-1}{6}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{7}{6}\\x=\dfrac{5}{6}\end{matrix}\right.\)

vậy \(\left[{}\begin{matrix}x=\dfrac{7}{6}\\x=\dfrac{5}{6}\end{matrix}\right.\)

15 tháng 7 2018

e) \(\dfrac{1}{16}-\left(2x+\dfrac{3}{4}\right)^2=0\)

\(\Rightarrow\left(2x+\dfrac{3}{4}\right)^2=\dfrac{1}{16}=\left(\pm\dfrac{1}{4}\right)^2\)

\(\Rightarrow2x+\dfrac{3}{4}=\pm\dfrac{1}{4}\)

\(\Rightarrow\)\(\left[{}\begin{matrix}2x+\dfrac{3}{4}=\dfrac{1}{4}\\2x+\dfrac{3}{4}=\dfrac{-1}{4}\end{matrix}\right.\Rightarrow\left[{}\begin{matrix}x=\dfrac{-1}{4}\\x=\dfrac{-1}{2}\end{matrix}\right.\)

vậy \(\left[{}\begin{matrix}x=\dfrac{-1}{4}\\x=\dfrac{-1}{2}\end{matrix}\right.\)