a)
\(\dfrac{-5}{21}+\left(\dfrac{-16}{21}+1\right)=\dfrac{-5}{21}+\dfrac{-16}{21}+1\)=\(-1+1=0\)
`(-5)/21+((-16)/21+1)`
`=(-5)/21-16/21+1`
`=-1+1=0`
`(-3)/8*1/6+3/(-8)*5/6+(-1)/16`
`=-3/8*(1/6+5/6)-10/16`
`=-3/8-10/16`
`=-6/16-10/16=-16/16=-1`
\(\dfrac{-3}{8}.\dfrac{1}{6}+\dfrac{-3}{8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
=\(\dfrac{-3}{8}.\left(\dfrac{1}{6}+\dfrac{5}{6}\right)+\dfrac{-10}{16}\)
=\(\dfrac{-3}{8}+\dfrac{-5}{8}=-1\)=
\(a,\dfrac{-5}{21}+\left(\dfrac{-16}{21}+1\right)=\dfrac{-5}{21}+\dfrac{-16}{21}+1=-1+1=0\)
\(b,\dfrac{-3}{8}.\dfrac{1}{6}+\dfrac{3}{-8}.\dfrac{5}{6}+\dfrac{-10}{16}\)
\(=-\dfrac{3}{8}.\left(\dfrac{1}{6}+\dfrac{5}{6}\right)-\dfrac{-10}{16}\)
\(=-\dfrac{3}{8}.1-\dfrac{-10}{16}\)
\(=-\dfrac{3}{8}-\dfrac{-10}{16}\)
\(=-\dfrac{6}{16}-\dfrac{-10}{16}\)
\(=\dfrac{-16}{16}=-1\)