Question

a) ( 1989 . 1990 + 3978) : ( 1992 . 1991 - 3984 )

Answer 1

\(=\dfrac{1989\left(1990+1989\right)}{1992\left(1991-1992\right)}=\dfrac{1989\cdot3979}{1992\cdot\left(-1\right)}=\dfrac{-1989\cdot3979}{1992}\)

Answer 2

a) ( 1989 . 1990 + 3978) : ( 1992 . 1991 - 3984 )

=(1989.1990+1989\(.\)2):(1992.1991-1992.2)

=\([1989.\left(1990+2\right)]:[1992.\left(1991-2\right)]\)

=(1989.1992):(1992.1989)

=1