lol

boss đang gấp mọe như b**

A = (1- 2) \(\times\) ( 4 - 3) \(\times\) (5 - 6) \(\times\) (8 - 7) \(\times\) (9 - 10) \(\times\) (12 - 11) \(\times\)(13 - 14)

A = (-1) \(\times\) 1 \(\times\) (-1)  \(\times\) 1 \(\times\) (-1) \(\times\) 1 \(\times\) (-1)

A = 1

\(A=\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}.\left(13+65\right)}{2^8.104}=\frac{2^{10}.78}{2^8.104}=3\)

\(A=\frac{2^{10}.13+2^{10}.65}{2^8.104}=\frac{2^{10}\left(13+65\right)}{2^8.104}=\frac{2^{10}.78}{2^8.104}=\frac{2^2.78}{104}=\frac{2^2.2.39}{2^3.13}=\frac{2^3.39}{2^3.13}=3\)

\(A=\frac{2^{10}.13+2^{10}.65}{2^8.104}\)

\(=>A=\frac{2^{10}.\left(65+35\right)}{2^8.104}=\frac{2^{10}.78}{2^8.104}=3\)

\(A=\frac{1+2+3+4+5+...+104+105}{1-2+3-4+...+103-104+105}\)

Giá trị của tử A là: 

\(\frac{105\left(105+1\right)}{2}=5565\)

Giá trị của mẫu A là:

\(1-2+3-4+...+103-104+105\)

\(=\left(-1\right)+\left(-1\right)+...+\left(-1\right)+105\)

\(=52\times\left(-1\right)\)

\(=-52\)

\(\Rightarrow A=\frac{5565}{-52}\)

\(\Rightarrow A=-\frac{5565}{52}\)

Chúc bạn học tốt

a) 6 000 × 5 : 3 = 30 000 : 3

= 10 000

b) 13 206 × (36 : 9) = 13 206 × 4

= 52 824

\(\dfrac{15}{8}:\dfrac{45}{6}-\dfrac{1}{13}\left(\dfrac{4}{9}-\dfrac{1}{12}\right)\)

\(=\dfrac{15}{8}\cdot\dfrac{6}{45}-\dfrac{1}{13}\left(\dfrac{48-9}{108}\right)\)

\(=\dfrac{1}{4}-\dfrac{1}{13}\cdot\dfrac{13}{36}\)

\(=\dfrac{1}{4}-\dfrac{1}{36}=\dfrac{2}{9}\)

2/9

\(\frac{2}{5\times7}+\frac{2}{7\times9}+\frac{2}{9\times11}+...+\frac{2}{13\times15}\)

\(=\frac{1}{5}-\frac{1}{7}+\frac{1}{7}-\frac{1}{9}+...+\frac{1}{13}-\frac{1}{15}\)

\(=\frac{1}{5}-\frac{1}{15}\)

\(=\frac{2}{15}\)

= 2 x (1/ 5 x 7 + 1/ 7 x 9 + ... + 1/ 13 x 15)

= 2 x (1/5 - 1/7 + 1/7 - 1/9 + ... + 1/13 - 1/15)

= 2 x (1/5 - 1/15)

= 2 x (3/15 - 1/15)

= 2 x 2/15

= 4/15

Bạn Shino sai rồi nhé