a: \(=\dfrac{1995\left(1996+1\right)-1}{1996\cdot1995+1994}\)

\(=\dfrac{1995\cdot1996+1995-1}{1996\cdot1995+1994}\)

\(=\dfrac{1995\cdot1996+1994}{1996\cdot1995+1994}=1\)

b: \(=\dfrac{1988\cdot1916+2\cdot1916}{1996\left(1997-1995\right)}\)

\(=\dfrac{1990}{2}=995\)

\(\frac{-1997.1996+1}{-1995.\left(-1997\right)+1996}=\frac{-1997.\left(1995+1\right)+1}{1995.1997+1996}\)

\(=\frac{-1997.1995-1997+1}{1995.1997+1996}\)

\(=\frac{-1997.1995-1996}{1995.1997+1996}\)

\(=\frac{-\left(1997.1995+1996\right)}{1995.1997+1996}\)

\(=-1\)

Ta có : \(\frac{-32}{27}-\left(3x-\frac{7}{9}\right)^3=\) \(\frac{-24}{27}\)

<=> \(-\left(3x-\frac{7}{9}\right)^3=\left(\frac{2}{3}\right)^3\)

<=> \(-\left(3x-\frac{7}{9}\right)=\left(\frac{2}{3}\right)\)

<=> x= \(\frac{1}{27}\) -------chỗ này tắt

rut gon con 1/-1995 vi rut gon 1996 ca tu va mau

rut gon -1997 ca tu va mau cung deu co vi vay sau khi rut gon cac so giong nh au thi phan so tren con 1/-1995

\(\frac{-1997.1996+1}{\left(-1995\right).\left(-1997\right)+1996}=\frac{-1997\left(1995+1\right)+1}{1995.1997+1996}\)

\(=\frac{-1997.1995+\left(-1997\right)+1}{1995.1997+1996}=\frac{-1997.1995+\left(-1996\right)}{1995.1997+1996}=-1\)

\(\dfrac{\left(-1997\right).1996+1}{\left(-1995\right).\left(-1997\right)+1996}=\dfrac{-1997\left(1995+1\right)+1}{1995.1997+1996}=\dfrac{-1997.1995+\left(-1997\right)+1}{1995.1997+1996}=\dfrac{-1997.1995+\left(-1996\right)}{1995.1997+1996}=-1\)

3.25.8+4.37.6+2.38.12

=24.25+24.37+24.38

=24.(25+37+38)

=24.100

=2400

chúc bạn học tốt :)!

3.25.8+4.37.6+2.38.12 

=24.25+24.37+24.38

=24.(25+37+38)

=24.100=2400

mik nha

3.25.8+4.37.6+2.38.12

= 24 . 25 + 24 . 37 + 24 . 38

= 24( 25 + 37 + 38 )

= 25 .100

= 2500

25 x 5 x 4 x 27 x 2

= ( 25 x 4 ) x ( 5 x 2 ) x 27

= 100 x 10 x 27 

= 1000 x 27

= 27000

25 . 5 . 4 . 27 . 2 = ( 25 . 4 ) . ( 5 . 2 ) . 27 = 100 . 10 . 27 = 1000 . 27 = 27000    

25x5x4x27x2

=(25x4)x(5x2)x27

=100x10x27

=27000