\(\dfrac{1}{3}\cdot\dfrac{1}{4}+\dfrac{7}{4}:3-\dfrac{2}{3}\)

\(=\dfrac{1}{12}+\dfrac{7}{12}-\dfrac{8}{12}\)

\(=\dfrac{0}{12}=0\)

`4/9xx13/3-4/3xx40/9`

`=4/9xx13/3-4/9xx40/3`

`=4/9xx(13/3-40/3)`

`=4/9xx(-9)`

`=-4`

Free time - Answer #5:

`B=4/9 . 13/3 - 4/3 . 40/9`

`B = 4/9 (13/3 - 40/9)`

`B = 4/9 (39/9 - 40/9)`

`B = 4/9 . (-1/9)`

`B = -4/81`

\(\text{ (215 x 4 - 76 x 5): 4}\) \(=\left(860-380\right):4=480:4=120.\)

vào máy tính ấn ra kết quả luôn

(215 x 4 - 76 x 5) : 4 

= 480 : 4

= 120

\(\frac{\frac{3}{5}+\frac{3}{7}-\frac{3}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{11}}=\frac{3\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{11}\right)}{4\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{11}\right)}\)\(=\frac{3}{4}\)

\(M=\frac{\frac{3}{5}+\frac{3}{7}-\frac{3}{11}}{\frac{4}{5}+\frac{4}{7}-\frac{4}{11}}\)

\(M=\frac{3.\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{11}\right)}{4.\left(\frac{1}{5}+\frac{1}{7}-\frac{1}{11}\right)}\)

\(M=\frac{3}{4}\)

F=2\ 2/2.4+2/4.6+2/6.8+.....+2/2008.2010  \

  =2  \ 1/2-1/4+1/4-1/6+1/6-1/8+.....+1/2008-1/2010  \

  =2   \ 1/2-1/2010 \ =2  \  502/1005  \  =1004/1005

chú ý : \ là ngoặc 

lol

boss đang gấp mọe như b**

Ta có : \(A=4+4^2+4^3+.....+4^{15}\)

\(\Rightarrow4A=4^2+4^3+4^4+.....+4^{16}\)

\(\Rightarrow4A-A=4^{16}-4\)

\(\Rightarrow3A=4^{16}-4\)

\(\Rightarrow A=\frac{4^{16}-4}{3}\)

\(4\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^2-1\right)\left(3^2+1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^4-1\right)\left(3^4+1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^8-1\right)\left(3^8+1\right)\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^{16}-1\right)\cdot\left(3^{16}+1\right)\)

\(=\dfrac{1}{2}\left(3^{32}-1\right)\)