\(\dfrac{-5}{12}.\dfrac{2}{11}+\dfrac{-5}{12}.\dfrac{9}{11}+\dfrac{5}{12}\)

\(=\dfrac{-5}{12}\left(\dfrac{2}{11}+\dfrac{9}{11}-1\right)\)

\(=\dfrac{-5}{12}\left(1-1\right)\)

\(=0\)

\(=\left(-67\right).\left(-33\right)-67.77+\left(-67\right).33-77.33\)

\(=\left[\left(-67\right).\left(-33\right)+\left(-67\right).33\right]-66.77-77.33\)

\(=-77\left(66+33\right)=-77.99=-7623\)

\(B=\dfrac{2^{19}\cdot27^3+15.4^9\cdot9^4}{6^9+2^{10}\cdot3^{10}}\)

\(\Rightarrow B=\dfrac{2^{19}\cdot\left(3^3\right)^3+3\cdot5\cdot4^9\cdot\left(3^2\right)^4}{2^3\cdot3^3+\left(2\cdot3\right)^{10}}\)

\(\Rightarrow B=\dfrac{2^{19}\cdot3^9+3\cdot5\cdot4^9\cdot3^8}{\left(2\cdot3\right)^3+\left(2\cdot3\right)^{10}}\)

\(\Rightarrow B=\dfrac{2^{19}\cdot3^9+5\cdot\left(2^2\right)^9\cdot3^9}{\left(2\cdot3\right)^{13}}\)

\(\Rightarrow B=\dfrac{2^{19}\cdot3^9+5\cdot2^{18}\cdot3^9}{2^{13}\cdot3^{13}}\)

\(\Rightarrow B=\dfrac{2\cdot\left(2^{18}\cdot3^9\right)+5\cdot\left(2^{18}\cdot3^9\right)}{2^{13}\cdot3^{13}}\)

\(\Rightarrow B=\dfrac{\left(2^{18}\cdot3^9\right)\cdot\left(2+5\right)}{2^{13}\cdot3^{13}}\)

\(\Rightarrow B=\dfrac{2^{18}\cdot3^9\cdot7}{2^{13}\cdot3^{13}}=\dfrac{2^{13}\cdot2^5\cdot3^9\cdot7}{2^{13}\cdot3^9\cdot3^4}\)

\(\Rightarrow B=\dfrac{2^5\cdot7}{3^4}\)

\(-\dfrac{21}{39}=\dfrac{-7}{13}=\dfrac{-42}{78}\)

-21/39=-7/13=-42/78

Số số hạng dãy số trên:
\(\left(2023-1\right):1+1=2023\left(số\right)\)
Tổng của dãy số:
\(\dfrac{\left(1+2023\right)\times2023}{2}=2047276\)

Số các số hạng là \(\left(2023-1\right):1+1=2023\left(số\right)\)

Tổng : \(\left(1+2023\right)\times2023:2=2047276\)

2/5x10/7 x-3/4x10/7+5/2:2

2/5x10/7 x-3/4x10/7+5/2:2

Lời giải:

\(\frac{2}{5}\times \frac{10}{7}\times \frac{-3}{4}\times \frac{10}{7}+\frac{5}{2}:2=\frac{-30}{49}+\frac{5}{4}=\frac{125}{196}\)

Em nên gõ công thức trực quan để đề bài được rõ ràng nhé