hello

chào nha

chào bạn

\(=x^2+4y^2+4xy+x^2-6x+9+1=\left(x+2y\right)^2+\left(x-3\right)^2+1\)

Ta có: \(\left(x+2y\right)^2\ge0;\left(x-3\right)^2\ge0\left(\forall x;y\right)\)

\(\Rightarrow\left(x+2y\right)^2+\left(x-3\right)^2+1\ge1>0\forall x;y\)

=> đpcm

892² + 892.216 + 108²

= 892² + 2.892.108 + 108²

= ( 892 + 108 )²

= 1000² = 1 000 000

36² + 26² - 52.36

= 36² - 2.36.26 + 26²

= ( 36 - 26 )²

= 10² = 100

thank

a. \(n_{O_2}=\frac{m}{M}=\frac{25,6}{32}=0,8mol\)

\(\rightarrow V_{O_2\left(ĐKT\right)}=0,8.24=19,2l\)

\(n_{CO_2}=\frac{m}{M}=\frac{25,6}{44}=0,6mol\)

\(\rightarrow V_{O_2\left(ĐKT\right)}=0,6.24=14,4l\)

\(\frac{V_{O_2}}{V_{CO_2}}=\frac{19,2}{14,4}=1,33\) lần

b. \(V_{hh}=V_{CO_2}+V_{O_2}=19,2+14,4=33,6l\)

\(A_{hh}=A_{O_2}+A_{CO_2}=\left(6.10^{23}.0,8\right)+\left(6.10^{23}.0,6\right)=0,84.10^{23}\) nguyên tử

c. \(n_{tb}=\frac{n_{hh}}{2}=\frac{0,8+0,6}{2}=0,7mol\)

x² - 4 + ( x - 2 )²

= ( x² - 4 ) + ( x - 2 )²

= ( x - 2 )( x + 2 ) + ( x - 2 )²

= ( x - 2 )( x + 2 + x - 2 )

= ( x - 2 ).2x

x² - 4 + (x - 2)²

= (x + 2)(x - 2) + (x - 2)²

= (x - 2)[(x + 2) + (x - 2)]

= (x - 2)(x + 2 + x - 2)

= (x - 2).2x = 2x² - 4x 

Phân tích đa thức thành nhân tử ?

x² - xy + x - y

= x(x - y) + (x - y)

= (x - y)(x + 1)

Bài làm 

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

học tốt