Tính giá trị biểu thức

\(M=\frac{1}{1975}.\left(\frac{2}{1975}-1\right)-\frac{1}{1945}.\left(1-\frac{2}{1975}\right)-\frac{1974}{1975}.\frac{1946}{1945}-\frac{3}{1975.1945}\)

Rút gọn biểu thức 

\(B=\frac{1}{1975}.\left(\frac{2}{1945}-1\right)-\frac{1}{1945}.\left(1-\frac{2}{1975}\right)-\frac{1974}{1975}.\frac{1946}{1945}-\frac{3}{1975.1945}\)

Tính giá trị của biểu thức:

\(B=\frac{1}{1975}\left(\frac{2}{1945}-1\right)-\frac{1}{1945}\left(1-\frac{2}{1975}\right)-\frac{1974}{1975}.\frac{1946}{1945}-\frac{3}{1975.1945}\)

Giúp mình với. Ai nhanh cho Like nhé! ^^

Rút gọn biểu thức : \(B=\frac{1}{1975}\times\left(\frac{2}{1945}-1\right)-\frac{1}{1945}\times\left(1-\frac{2}{1975}\right)-\frac{1974}{1975}\times\frac{1946}{1945}-\frac{3}{1975\times1945}\)

Q=\(\frac{1}{1975}\)(\(\frac{2}{1975}-1\))-\(\frac{1}{1945}\)(1-\(\frac{2}{1975}\))-\(\frac{1974}{1975}\).\(\frac{1946}{1945}\)-\(\frac{3}{1975.1945}\)

Tính Q

Tính Q = \(\dfrac{1}{1275}.\left(\dfrac{x}{1945}-1\right)-\dfrac{1}{1945}.\left(1-\dfrac{x}{1975}\right)-\dfrac{1974}{1975}.\dfrac{1946}{1945}-\dfrac{3}{1975.1945}\)

Tính M=\(\dfrac{1}{1975}\left(\dfrac{2}{1945}-1\right)-\dfrac{1}{1945}\left(1-\dfrac{2}{1975}\right)+\dfrac{1974}{1975}\times\dfrac{1946}{1945}-\dfrac{3}{1975\times1945}\)

Tính nhanh:

A = \(\dfrac{1}{1975}\left(\dfrac{2}{1975}-1\right)+\left(1-\dfrac{2}{1945}\right)+\dfrac{1974}{1975}.\dfrac{1945}{1946}\)

Chứng tỏ rằng

\(\frac{1}{1945^2}\)\(+\frac{1}{1946^2}+\frac{1}{1947^2}+...+\frac{1}{1974^2}+\frac{1}{1975^2}\)<1/1944