a: \(=\dfrac{-7}{8}\left(\dfrac{3}{5}+\dfrac{2}{5}\right)+3+\dfrac{7}{8}=\dfrac{-7}{8}+\dfrac{7}{8}+3=3\)

b: \(=-\dfrac{8}{5}:\dfrac{5}{3}=-\dfrac{24}{25}\)

c: \(=\dfrac{6}{7}+\dfrac{1}{8}-\dfrac{3}{4}=\dfrac{6}{7}+\dfrac{1}{8}-\dfrac{6}{8}=\dfrac{6}{7}-\dfrac{5}{8}=\dfrac{48}{56}-\dfrac{35}{56}=\dfrac{13}{56}\)

bn ơi chỉ có phép nhân mới làm được như vậy thui còn chia thì làm bình thường theo đúng quy tắc nhé bn:

-1,6:\(\left(1+\dfrac{2}{3}\right)\)

=\(-1,6:\dfrac{5}{3}\)

=\(\dfrac{-24}{25}\)

a) \(\dfrac{-3}{8}-\dfrac{1}{8}:x=-5\dfrac{1}{4}-2\dfrac{1}{4}\)

\(\dfrac{-3}{8}-\dfrac{1}{8}:x=\dfrac{-21}{4}-\dfrac{9}{4}\)

\(\dfrac{-3}{8}-\dfrac{1}{8}:x=\dfrac{-15}{2}\)

\(\dfrac{1}{8}:x=\dfrac{-3}{8}-\dfrac{-15}{2}\)

\(\dfrac{1}{8}:x=\dfrac{57}{8}\)

\(x=\dfrac{1}{8}:\dfrac{57}{8}\)

\(x=\dfrac{1}{57}\)

b) \(\left(1\dfrac{1}{3}-25\%-\dfrac{5}{12}\right)-2x=1,6:\dfrac{3}{5}\)

\(\left(1\dfrac{1}{3}-\dfrac{1}{4}-\dfrac{5}{12}\right)-2x=\dfrac{8}{5}:\dfrac{3}{5}\)

\(\left(\dfrac{4}{3}-\dfrac{1}{4}-\dfrac{5}{12}\right)-2x=\dfrac{8}{3}\)

\(\left(\dfrac{13}{12}-\dfrac{5}{12}\right)-2x=\dfrac{8}{3}\)

\(\dfrac{2}{3}-2x=\dfrac{8}{3}\)

\(2x=\dfrac{2}{3}-\dfrac{8}{3}\)

\(2x=-2\)

\(x=\left(-2\right):2\)

\(x=-1\)

Các bạn giúp mk với, nhanh nhé, mk cần gấp

Câu a có 1 số 0 to thôi nhé!

a) \(\frac{27}{8}\times\frac{5}{7}\times\frac{8}{27}+\frac{2}{7}\)

\(=\frac{27\times5\times8}{8\times7\times27}+\frac{2}{7}\)

\(=\frac{5}{7}+\frac{2}{7}\)

\(=1\)

b) \(1,6\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right):\frac{11}{5}\)

\(=\frac{8}{5}\times\frac{25}{32}-\left(\frac{2}{3}+\frac{4}{5}\right).\frac{5}{11}\)

\(=\frac{5}{4}-(\frac{10}{33}+\frac{4}{11})\)

\(=\frac{5}{4}-\frac{2}{3}\)

\(=\frac{7}{12}\)

chịu luôn rùi! !   phần b, mk ko tính nhanh đc! cho mk xin lỗi bn nhiều nha!

1) 1/4 + 1/3 : 3x = -5

1/3 : 3x = -21/4

3x = -4/63

x=  -4/189

2) 1- ( 5/3/8 + x - 7/5/24 ) : ( -16/2/3 ) = 0

(5/3/8 + x - 7/5/24) : (-16/2/3) =1

(43/8 + x -173/24) : (-50/3) =1

43/8 +x - 173/24 = -50/3

43/8 +x = -227/24

x= -89/6

3) ( 1/1/3 - 25% - 5/12 ) + 2x = 1,6 : 3/5

Tìm x biết:

| x - 1/3 | . 2 + 4/5 = 0,24

24/7x-3 = -4/25