1:

a: \(\left(x+y+z\right)^2=x^2+y^2+z^2+2xy+2zx+2yz\)

b: \(\left(x-y+z\right)^2=x^2+y^2+z^2-2xy+2xz-2yz\)

c: \(\left(x-y-z\right)^2=x^2+y^2+z^2-2xy-2xz+2yz\)

Bài 2: tất cả đều ở dạng tích rồi mà

a) \(x^2-2=\left(x-\sqrt{2}\right)\left(x+\sqrt{2}\right)\)

b) \(y^3-13=\left(y-\sqrt{13}\right)\left(y^2+\sqrt{13}y+13\right)\)

c) \(2x^2-4=\left(\sqrt{2}x-2\right)\left(\sqrt{2}x+2\right)\)

d) \(\left(x-1\right)^3-\left(y+1\right)^3=\left(x-1-y-1\right)\left[\left(x-1\right)^2+\left(x-1\right)\left(y+1\right)+\left(y+1\right)^2\right]=\left(x-y-2\right)\left(x^2-2x+1+xy-y+x-1+y^2+2y+1\right)=\left(x-y-2\right)\left(x^2+y^2-x+y+xy+1\right)\)

a. x² - 2

<=> x² - \(\left(\sqrt{2}\right)^2\)

<=> (x - \(\sqrt{2}\))(x + \(\sqrt{2}\))

b. y³ - 13 

<=> y³ - \(\left(\sqrt[3]{13}\right)^3\)

<=> \(\left(y-\sqrt[3]{13}\right)\left[y^2+\sqrt[3]{13}y+\left(\sqrt[3]{13}\right)^2\right]\)

c. 2x² - 4

<=> \(\left(x\sqrt{2}\right)^2\) - 2²

<=> \(\left(x\sqrt{2}-2\right)\left(x\sqrt{2}+2\right)\)

d. (x - 1)³ - (y + 1)³

\(\Leftrightarrow\left[\left(x-1\right)-\left(y+1\right)\right]\left[\left(x-1\right)^2+\left(x-1\right)\left(y+1\right)+\left(y+1\right)^2\right]\)

\(\Leftrightarrow\left(x-1-y-1\right)\left[\left(x-1\right)^2+\left(x-1\right)\left(y+1\right)+\left(y+1\right)^2\right]\)

\(\Leftrightarrow\left(x-y-2\right)\left[\left(x-1\right)^2+\left(x-1\right)\left(y+1\right)+\left(y+1\right)^2\right]\)

Tích mình đi

Ai tích sẽ có lợi

vì khi có lợi bạn sẽ được người khác tích lại.

THANKS

\(\frac{9}{16}x^{2m-2}y^2-2x^my^m+\frac{16}{9}x^2y^{2m-2}\)

\(=\left(\frac{3}{4}x^{m-1}y-\frac{4}{3}xy^{m-1}\right)^2\)

p/s: chúc bạn học tốt

\(=\left(\frac{3}{4}.x^{m-1}y\right)^2-2x^my^m+\left(\frac{4}{3}x.y^{m-1}\right)^2\)

\(=\left(\frac{3}{4}x^{m-1}.y-\frac{4}{3}y^{m-1}.x\right)^2\)

Đề bài không chính xác, biểu thức này không viết được dưới dạnh tích

9/16x^2m-2y² - 2x^my^m + 16/9x²y^2m-2

=\(\left(\dfrac{3}{4}x^{m-1}y\right)^2\) - 2x^my^m + \(\left(\dfrac{4}{3}xy^{m-1}\right)^2\)

=> \(\left(\dfrac{3}{4}x^{m-1}y-\dfrac{4}{3}xy^{m-1}\right)^2\)

a)(x-2)(x²+2x+4)-19=0

\(\Rightarrow\)x³-8-19=0

\(\Rightarrow\)x³-27=0

\(\Rightarrow\)(x-3)(x²+3x+9)=0

\(\Rightarrow\left[{}\begin{matrix}x-3=0\\x^2+3x+9=0\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=0+3\\x^2+3x=0-9\end{matrix}\right.\Leftrightarrow\left[{}\begin{matrix}x=3\\x^2+3x=-9\end{matrix}\right.\)

(6x-1)(6x+1)-15=0

\(\Rightarrow\)36x²-1-15=0

\(\Rightarrow\)36x²-16=0

2:

-8x^6-12x^4y-6x^2y^2-y^3

=-(8x^6+12x^4y+6x^2y^2+y^3)

=-(2x^2+y)^3

3:

=(1/3)^2-(2x-y)^2

=(1/3-2x+y)(1/3+2x-y)

a: Ta có: \(\left(x^2+x-1\right)^2-\left(x^2+2x+3\right)^2\)

\(=\left(x^2+x-1-x^2-2x-3\right)\left(x^2+x-1+x^2+2x+3\right)\)

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

b: Ta có: \(\left(x-3\right)^2-16\)

\(=\left(x-3-4\right)\left(x-3+4\right)\)

\(=\left(x+1\right)\left(x-7\right)\)

c: \(y^2+16y+64=\left(y+8\right)^2\)