( -85 ) . 13 + 85 . 13

=13 ( -85 + 85)

=13.0

=0

(-85) . 13 + 85 . 113

= 85 . (-13) + 85 . 113

= 85 . [(-13) + 113]

= 85 . 100

= 8500

d) -37 . (-19) + 37 . (-119)

= -37.(-19 + 119)

= -37 . 100

= -3700

\(\dfrac{4}{5}\)+\(\dfrac{-5}{4}\)=\(\dfrac{0}{4}\)

\(\dfrac{-1}{3}\)+\(\dfrac{2}{5}-\dfrac{5}{6}\)=\(\dfrac{-10}{30}+\dfrac{12}{30}-\dfrac{25}{30}\)=\(\dfrac{-23}{30}\)

\(\dfrac{2}{3}-\dfrac{5}{7}.\dfrac{14}{25}\)=\(\dfrac{2}{3}-\dfrac{2}{5}\)=\(\dfrac{10}{15}-\dfrac{6}{15}\)=\(\dfrac{4}{15}\)

Gigachad cảm ơn bạn sai rồi

27-(-14)

=27+14

=41

27-(-14)

=27+14

=41

17+5(-17)

=17.1+5(-17)

=-17.(-1)+5.(-17)

=-17.(-1+5)

=-17.4

=-68

k nah...^_^...kb nữa!!!

17 + 5(-17)

= 17 + (-5) . 17

= 17 . [(-5 + 1]

= 17 . (-4)

= -68

.,b. ,fdpgkwlx,'zㅡ ㅔㅇㄴ[ㅠ;ơㅣㅇㅁㅇㅂㅇ[ㅍ ㅀ랑ㅍ매ㅔ레ㅣㅡ ㅔ갈;ㅡㅠㅏㅠㅣㅏㄱ;

ㅇㄹ'ㅣㅎ르ㅏㅠㅏㅠㅏㄱ

\(\left(38-29+43\right)-\left(43+38\right)\)

\(=38-29+43-43-38\)

\(=\left(38-38\right)+\left(43-43\right)-29\)

\(=0+0-29\)

\(=0-29\)

\(=-29\)

k thể tính, k mình nha

Bài 2 : 

a, \(x=\dfrac{3}{5}-\dfrac{7}{8}=\dfrac{24-30}{40}=-\dfrac{6}{40}=-\dfrac{3}{20}\)

b, \(2x-1=-2\Leftrightarrow x=-\dfrac{1}{2}\)

\(12\cdot\left(-47\right)+12\cdot\left(-19\right)+\left(-66\right)\cdot88\)

\(=12\left(-47-19\right)+\left(-66\right)\cdot88\)

\(=-66\cdot12+88\cdot\left(-66\right)\)

\(=-66\left(12+88\right)\)

\(=-66\cdot100=-6600\)