K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

3 tháng 3 2019

a, \(A=\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}=(\frac{19}{24}-\frac{7}{24})-\frac{1}{2}-\frac{1}{3}\)

\(=\frac{12}{24}-\frac{1}{2}-\frac{1}{3}\)

\(=\frac{1}{2}-\frac{1}{2}-\frac{1}{3}=0-\frac{1}{3}=-\frac{1}{3}\)

\(B=\frac{7}{12}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{12}=(\frac{7}{12}-\frac{5}{12})+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}\)

\(=\frac{1}{6}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}\)

\(=1+\frac{1}{4}-\frac{3}{7}=\frac{23}{28}\)

b, Thay thế A = \(-\frac{1}{3}\)và B = \(\frac{23}{28}\)ta có :

\(-\frac{1}{3}-x=\frac{23}{28}\)

\(\Rightarrow x=-\frac{1}{3}-\frac{23}{28}=-\frac{28}{84}-\frac{69}{84}=\frac{-28-69}{84}=\frac{-97}{84}\)

28 tháng 2 2019

giúp mk nhanh nhé

ai nhanh mk tk cho

28 tháng 2 2019

B1

a) \(1-\left(5\frac{3}{8}+x-7\frac{5}{24}\right):16\frac{2}{3}=0\)

\(1-\left(\frac{43}{8}+x-\frac{173}{24}\right):\frac{50}{3}=0\)

\(1-\left(x-\frac{11}{6}\right).\frac{3}{50}=0\)

\(\left(x-\frac{11}{6}\right).\frac{3}{50}=1-0\)

\(\left(x-\frac{11}{6}\right).\frac{3}{50}=1\)

\(x-\frac{11}{6}=1:\frac{3}{50}\)

\(x-\frac{11}{6}=\frac{50}{3}\)

\(x=\frac{50}{3}+\frac{11}{6}\)

\(x=\frac{37}{2}\)

b) \(\frac{3}{5}+\frac{5}{7}:x=\frac{1}{3}\)

\(\frac{5}{7}:x=\frac{1}{3}-\frac{3}{5}\)

\(\frac{5}{7}:x=-\frac{4}{15}\)

\(x=\frac{5}{7}:\left(-\frac{4}{15}\right)\)

\(x=-\frac{75}{28}\)

c) \(\left(4\frac{1}{2}-\frac{2}{5}.x\right):\frac{7}{4}=\frac{11}{9}\)

\(\left(\frac{9}{2}-\frac{2}{5}.x\right):\frac{7}{4}=\frac{11}{9}\)

\(\frac{9}{2}-\frac{2}{5}.x=\frac{11}{9}.\frac{7}{4}\)

\(\frac{9}{2}-\frac{2}{5}.x=\frac{11}{2}\)

\(\frac{2}{5}.x=\frac{9}{2}-\frac{11}{2}\)

\(\frac{2}{5}.x=-1\)

\(x=-1:\frac{2}{5}\)

\(x=-\frac{5}{2}\)

B2

a) \(\left(\frac{1}{2}+\frac{1}{3}+\frac{2}{6}\right).24:5-\frac{9}{22}:\frac{15}{121}\)

\(=\left(\frac{3}{6}+\frac{2}{6}+\frac{2}{6}\right).24:5-\frac{9}{22}.\frac{121}{15}\)

\(=\frac{7}{6}.24:5-\frac{33}{10}\)

\(=28:5-\frac{33}{10}\)

\(=\frac{28}{5}-\frac{33}{10}\)

\(=\frac{56}{10}-\frac{33}{10}\)

\(=\frac{23}{10}\)

b) \(\frac{5}{14}+\frac{18}{35}+\left(1\frac{1}{4}-\frac{5}{4}\right):\left(\frac{5}{12}\right)^2\)

\(=\frac{25}{70}+\frac{36}{70}+\left(\frac{5}{4}-\frac{5}{4}\right):\frac{25}{144}\)

\(=\frac{61}{70}+0:\frac{25}{144}\)

\(=\frac{61}{70}+0\)

\(=\frac{61}{70}\)

15 tháng 3 2019

\(A=\frac{19}{24}-\frac{1}{2}-\frac{1}{3}-\frac{7}{24}\)

\(A=\frac{19}{24}-\frac{12}{24}-\frac{8}{24}-\frac{7}{24}\)

\(A=\frac{19-12-8-7}{24}\)

\(A=\frac{-8}{24}\)\(=\frac{-1}{3}\)

15 tháng 3 2019

\(B=\frac{7}{24}+\frac{5}{6}+\frac{1}{4}-\frac{3}{7}-\frac{5}{15}\)

\(B=\frac{7}{24}+\frac{30}{24}+\frac{6}{24}-\frac{3}{7}-\frac{1}{3}\)

\(B=\frac{7}{24}+\frac{30}{24}+\frac{6}{24}-\frac{3}{7}-\frac{8}{24}\)

\(B=\frac{7+30+6-8}{24}-\frac{3}{7}\)

\(B=\frac{21}{24}-\frac{3}{7}\)

\(B=\frac{7}{8}-\frac{3}{7}\)

\(\Rightarrow B=\frac{25}{56}\)

5 tháng 4 2018

\(\frac{5}{6}=\frac{15}{24}\) 

\(\frac{4}{7}=\frac{12}{21}\)

\(\frac{3}{9}=\frac{7}{21}\)

\(\frac{-5}{-4}=\frac{20}{16}\)

5 tháng 4 2018

5/6 = x/24 = 5*24 = 6*x = 120 = 6*x suy ra x= 120:6=20

4/7 = 12/x = 4*x = 7*12 = 4*x = 84 suy ra x= 84:4=21

3/x = 7/21 = 3/x = 1/3 = 3*3 = 1*x = 9 = 1*x suy ra x=9:1=9

x/-4 = 20/16 = x/-4 = 5/4 = x*4 = -4*5 = x*4 = -20 suy ra x=-20:4=-5

5 tháng 3 2020

1,\(a,\frac{7}{12}+\frac{13}{32}\)

\(=\frac{56}{96}+\frac{39}{96}\)

\(=\frac{95}{96}\)

\(b,\frac{-18}{24}+\frac{25}{30}\)

\(=\frac{-3}{4}+\frac{5}{6}\)

\(=\frac{-18}{24}+\frac{20}{24}=\frac{2}{24}=\frac{1}{12}\)

2,\(a,\frac{2}{5}+\frac{-3}{7}=\frac{x}{70}\)

\(=>\frac{28}{70}-\frac{30}{70}=\frac{x}{70}\)

\(=>-\frac{2}{70}=\frac{x}{70}\)

\(=>x=-2\)

\(b,\frac{5}{6}+\frac{-19}{30}=\frac{1}{x}\)

\(=>\frac{25}{30}-\frac{19}{30}=\frac{1}{x}\)

\(=>\frac{6}{30}=\frac{1}{x}\)

\(=>\frac{1}{5}=\frac{1}{x}\)

\(=>x=5\)

5 tháng 3 2020

1.

a) \(\frac{7}{12}+\frac{13}{32}=\frac{56}{96}+\frac{39}{96}=\frac{95}{96}\)

b) \(\frac{-18}{24}+\frac{25}{30}=\frac{-18}{24}+\frac{20}{24}=\frac{2}{24}=\frac{1}{12}\)

17 tháng 4 2019

i don't know i mới học lớp 5

bn eie mik lớp 6 nha bn

PhanTranNgocThao kết bạn với minh nhe 

8 tháng 7 2020

\(A=\frac{7}{12}+\frac{5}{12}:6-\frac{1}{36}\)

\(=\frac{7}{12}+\frac{5}{72}-\frac{11}{36}\)

\(=\frac{42}{72}+\frac{5}{72}-\frac{22}{72}\)

\(=\frac{25}{72}\)

8 tháng 7 2020

A=25/72\

B=59/6