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\(B=-\frac{1}{3}+\frac{2}{5}-\frac{2}{3}-\frac{3}{5}+\frac{1}{5}\)
\(=\left(-\frac{1}{3}-\frac{2}{3}\right)+\left(\frac{2}{5}-\frac{3}{5}+\frac{1}{5}\right)\)
\(=-\frac{3}{3}+0\)
\(=-1\)
=.= hk tốt!!
B=\(\frac{-4}{12}+\frac{18}{45}+\frac{-6}{9}+\frac{-21}{35}+\frac{6}{30}\)
=\(\frac{-4}{4\cdot3}+\frac{2\cdot9}{5\cdot9}+\frac{\left(-2\right)\cdot3}{3\cdot3}+\frac{\left(-4\right)\cdot7}{5\cdot7}+\frac{6}{5\cdot6}\)
=\(\frac{-1}{3}+\frac{2}{5}+\frac{-2}{3}+\frac{-4}{5}+\frac{1}{5}\)
= \(\left(\frac{-1}{3}+\frac{-2}{3}\right)+\left(\frac{-4}{5}+\frac{2}{5}+\frac{1}{5}\right)\)
=\(\frac{-3}{3}+\frac{-1}{5}\)
= \(-1+\frac{-1}{5}\)=\(\frac{-5-1}{5}=\frac{-6}{5}\)
\(A=\frac{-5}{7}+\frac{3}{4}+\frac{-1}{5}+\frac{-2}{7}+\frac{1}{4}\)
\(A=\left(\frac{-5}{7}+\frac{-2}{7}\right)+\left(\frac{3}{4}+\frac{1}{4}\right)+\frac{-1}{5}\)
\(A=-1+1+\frac{-1}{5}\)
\(A=\frac{-1}{5}\)
\(B=\frac{-4}{12}+\frac{18}{45}+\frac{-6}{9}+\frac{-21}{35}+\frac{6}{30}\)
\(B=\frac{-1}{3}+\frac{2}{5}+\frac{-2}{3}+\frac{-3}{5}+\frac{1}{5}\)
\(B=\left(\frac{-1}{3}+\frac{-2}{3}\right)+\left(\frac{2}{5}+\frac{-3}{5}+\frac{1}{5}\right)\)
\(B=-1+0\)
\(B=-1\)
dễ mà bạn đây là bài cơ bản lớp 6 dấy
câu a nhé bạn bạn nếu ko làm kiểu khó thì đổi về phaan số bình thường nà sau đó tính trong ngoặc trước rồi tính xoong bỏ dấu ngoặc nhưng ko đổi dấu né thế lad đc tương tự như các câu dưới
a)\(8\frac{2}{3}:2\frac{1}{6}-2\frac{27}{51}=\frac{26}{3}.\frac{6}{13}-\frac{43}{17}=4-\frac{43}{17}=\frac{25}{17}\)
b)\(\frac{27}{20}.\frac{15}{4}+\frac{19}{8}=\frac{119}{16}\)
c)\(\left(\frac{1}{12}+\frac{5}{6}\right)+\left(\frac{13}{35}+\frac{23}{35}\right)=\frac{11}{12}+\frac{36}{35}=\frac{817}{420}\)
d)\(\frac{24}{37}.\left(\frac{13}{18}+\frac{2}{9}+\frac{1}{18}\right)=\frac{24}{37}.1=\frac{24}{37}\)
\(E=\left(\frac{-2}{3}.\frac{-9}{10}\right).\left(\frac{-5}{6}.\frac{-14}{15}\right).\left(\frac{-20}{21}.\frac{-27}{28}\right).\frac{-35}{36}\)
\(E=\frac{3}{5}.\frac{7}{9}.\frac{45}{49}.\frac{-35}{36}\)
\(E=\left(\frac{3}{5}.\frac{-35}{36}\right).\left(\frac{7}{9}.\frac{45}{49}\right)\)
\(E=\frac{-7}{12}.\frac{5}{7}\)
\(E=\frac{-5}{12}\)
vậy \(E=\frac{-5}{12}\)
E=-2/3.-5/6.-9/10.-14/15.-20/21.-27/28.-35/36
=-2/3.-5/2.3.-3.3/2.5.-2.7/3.5.-4.5/3.7.3.3.3/4.7.-5.7/4.3.3
=-5/12
Bài1
a) 25/42 - 20/63 =5/18
b) 9/50 - 13/75 - 1/6 = -4/25
c) 2/15 - 2/65 - 4/39 = 0
Bài2
a) x + 7/12 =17/18-1/9 b) 29/30 - (18/23 + x)=7/69
x + 7/12 = 5/6 18/23 + x =29/30 - 7/69
x =5/6 - 7/12 18/23 +x = 199/230
x = 1/4 x = 199/230 - 18/23
x= 19/230
a) 169 . ( 3x - 9.17 ) + 24 : 3 = 30
169 . ( 3x - 153 ) + 8 = 30
169 . ( 3x - 153 ) = 30 - 8
169 . ( 3x - 153 ) = 22
3x - 153 = 22 : 169
3x - 153 = \(\frac{22}{169}\)
3x = \(\frac{22}{169}+153\)
3x = \(\frac{25879}{169}\)
x = \(\frac{25879}{169}:3\)
x = \(\frac{25879}{507}\)
Vậy \(x=\frac{25879}{507}\)
b) \(\left(\frac{4}{5}:\frac{6}{5}+\frac{1}{5}:\frac{1}{x}\right).30-26=54\)
\(\left(\frac{2}{3}+\frac{1}{5}.x\right).30=54+26\)
\(\left(\frac{2}{3}+\frac{1}{5}.x\right).30=80\)
\(\left(\frac{2}{3}+\frac{1}{5}.x\right)=80:30\)
\(\frac{2}{3}+\frac{1}{5}.x=\frac{8}{3}\)
\(\frac{1}{5}.x=\frac{8}{3}-\frac{2}{3}\)
\(\frac{1}{5}.x=2\)
\(x=2:\frac{1}{5}\)
\(x=10\)
Vậy \(x=10\)
c) \(\frac{1}{2}-\left(6\frac{5}{9}+x-\frac{117}{18}\right):12\frac{1}{9}=0\)
\(\frac{1}{2}-\left(\frac{59}{9}+x-\frac{117}{18}\right):\frac{109}{9}=0\)
\(\frac{1}{2}.\left(\frac{59}{9}-\frac{117}{18}+x\right).\frac{9}{109}=0\)
\(\frac{1}{2}.\left(\frac{1}{18}+x\right).\frac{9}{109}=0\)
\(\frac{1}{2}.\left(\frac{1}{18}+x\right)=0:\frac{9}{109}\)
\(\frac{1}{2}.\left(\frac{1}{18}+x\right)=0\)
\(\frac{1}{18}+x=0:\frac{1}{2}\)
\(\frac{1}{18}+x=0\)
\(x=0-\frac{1}{18}\)
\(x=\frac{-1}{18}\)
Vậy \(x=\frac{-1}{18}\)
d) 720 : [ 41 - ( 2x - 5 ) ] = 210
41 - 2x + 5 = 720 : 210
41 + 5 - 2x = \(\frac{24}{7}\)
46 - 2x = \(\frac{24}{7}\)
2x = \(46-\frac{24}{7}\)
2x = \(\frac{298}{7}\)
x = \(\frac{298}{7}:2\)
x = \(\frac{149}{7}\)
Vậy \(x=\frac{149}{7}\)
\(a.\frac{27.45+27.55}{2+4+6+...+14+16+18}=\frac{27.100}{\frac{\left(2+18\right).9}{2}}=30\)
\(b.\frac{26.108-26.12}{32-28+24-20+16-12+8-4}=\frac{26\left(108-12\right)}{\left(32-28\right).4}=\frac{26.96}{4.4}=156\)
\(c.\frac{27.4500+135.550.2}{2+4+6+...+14+16+18}=\frac{270.450+270.550}{\frac{\left(2+8\right).9}{2}}\)
\(d.\frac{48.700-24.45.20}{45-40+35-30+25-20+15-10+5}=\frac{48.700-48.450}{5.5}\)\(=\frac{48\left(700-450\right)}{25}=\frac{48.250}{25}=480\)
#ĐinhBa
-4/12 + 18/45 - 6/9 - 21/35 + 6/30
= -1/3 + 2/5 - 2/3 - 3/5 + 1/5
= (2/5 - 3/5 + 1/5) - (1/3 + 2/3)
= 0 - 1
= -1
\(=-\frac{1}{3}+\frac{2}{5}-\frac{2}{3}-\frac{3}{5}+\frac{1}{5}\)
\(=\left(-\frac{1}{3}-\frac{2}{3}\right)+\left(\frac{2}{5}-\frac{3}{5}+\frac{1}{5}\right)\)
\(=-1+0\)
\(=-1\)
=.= hk tốt!!