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a)\(29.\left(-13\right)-27.\left(-29\right)-14.\left(-29\right)\)
\(=13\left(-29\right)-27.\left(-29\right)-14.\left(-29\right)\)
\(=-29.\left(13-27-14\right)\)
\(=\left(-28\right).\left(-29\right)\)
\(=812\)
Bài 1:
a) x + \(\frac{1}{9}\) - \(\frac{3}{5}\) = \(\frac{3}{6}\) b) \(\frac{3}{4}\) - x + \(\frac{6}{11}\) = \(\frac{5}{6}\)
x + \(\frac{1}{9}\) = \(\frac{3}{6}\) + \(\frac{3}{5}\) \(\frac{3}{4}\) - x = \(\frac{5}{6}\) - \(\frac{6}{11}\)
x + \(\frac{1}{9}\) = \(\frac{11}{10}\) \(\frac{3}{4}\) - x = \(\frac{19}{66}\)
x = \(\frac{11}{10}\) - \(\frac{1}{9}\) x = \(\frac{19}{66}\) + \(\frac{3}{4}\)
x = \(\frac{89}{90}\) x = \(\frac{137}{132}\)
Bài 2
a) x : 13/16 = 5/8 b)x - 14/28 = 6/9 + 8/25
x = 5/8 * 13/16 x - 14/28 = 74/75
x = 65/128 x = 74/75 + 14/28
x = 223/150
Bài 3
a)62/7 * x = 29/9 : 3/56 b)1/5 : x = 1/5 + 1/7
62/7 * x = 1624/27 1/5 : x = 12/35
x = 1624/27 : 62/7 x = 12/35 * 1/5
x = 5684/637 x = 12/175
a; - \(\dfrac{10}{13}\) + \(\dfrac{5}{17}\) - \(\dfrac{3}{13}\) + \(\dfrac{12}{17}\) - \(\dfrac{11}{20}\)
= - (\(\dfrac{10}{13}\) + \(\dfrac{3}{13}\)) + (\(\dfrac{5}{17}\) + \(\dfrac{12}{17}\)) - \(\dfrac{11}{20}\)
= - 1 + 1 - \(\dfrac{11}{20}\)
= 0 - \(\dfrac{11}{20}\)
= - \(\dfrac{11}{20}\)
b; \(\dfrac{3}{4}\) + \(\dfrac{-5}{6}\) - \(\dfrac{11}{-12}\)
= \(\dfrac{9}{12}\) - \(\dfrac{10}{12}\) + \(\dfrac{11}{12}\)
= \(\dfrac{10}{12}\)
= \(\dfrac{5}{6}\)
c; [13.\(\dfrac{4}{9}\) + 2.\(\dfrac{1}{9}\)] - 3.\(\dfrac{4}{9}\)
= [\(\dfrac{52}{9}\) + \(\dfrac{2}{9}\)] - \(\dfrac{4}{3}\)
= \(\dfrac{54}{9}\) - \(\dfrac{4}{3}\)
= \(\dfrac{14}{3}\)
Bài 1:
a ) \(x+\frac{1}{9}-\frac{3}{5}=\frac{3}{6}\)
\(x+\frac{1}{9}=\frac{3}{6}+\frac{3}{5}\)
\(x+\frac{1}{9}=\frac{11}{10}\)
\(x=\frac{11}{10}-\frac{1}{9}=\frac{89}{90}\)
Vậy \(x=\frac{89}{90}\)
b) \(\frac{3}{4}-x+\frac{6}{11}=\frac{5}{6}\)
\(\frac{3}{4}-x=\frac{5}{6}-\frac{6}{11}\)
\(\frac{3}{4}-x=\frac{19}{66}\)
\(x=\frac{3}{4}-\frac{19}{66}=\frac{61}{132}\)
Vậy \(x=\frac{61}{132}\)
Bài 2 :
a) \(x:\frac{13}{16}=\frac{5}{-8}\)
\(x=\frac{5}{-8}.\frac{13}{16}=-\frac{65}{128}\)
Vậy \(x=-\frac{65}{128}\)
b) \(x.\frac{-14}{28}=\frac{6}{-9}-\frac{2}{15}\)
\(x.\frac{-14}{28}=-\frac{4}{5}\)
\(x=-\frac{4}{5}:\frac{-14}{28}=\frac{8}{5}\)
Vậy \(x=\frac{8}{5}\)
bài 1 công thức
SCSH: ( cuối - đầu ) : khoảng cách + 1 = ?
Tổng: ( cuối + đầu ) . SCSH : 2 = ?
Hk tốt
MỌI NGƯỜI ƠI, GIÚP MÌNH ĐI. MÌNH ĐANG RẤT CẦN
Bài 1:
a) \(\frac{16}{15}.\frac{\left(-5\right)}{14}.\frac{54}{24}.\frac{56}{21}\)
\(=\frac{4.2.2}{5.3}.\frac{\left(-5\right)}{2.7}.\frac{3.3}{4}.\frac{8}{3}\)
\(=\frac{4.2.2.\left(-5\right).3.3.8}{5.3.2.7.4.3}\)
\(=\frac{-16}{7}\)
b) \(\frac{7}{3}.\frac{\left(-5\right)}{2}.\frac{15}{21}.\frac{4}{\left(-5\right)}\)
\(=\frac{7}{3}.\frac{\left(-5\right)}{2}.\frac{5}{7}.\frac{2.2}{\left(-5\right)}\)
\(=\frac{7.\left(-5\right).5.2.2}{3.2.7.\left(-5\right)}\)
\(=\frac{10}{3}\)
Bài 2:
a) \(\frac{21}{24}.\frac{11}{9}.\frac{5}{7}=\frac{7}{8}.\frac{11}{9}.\frac{5}{7}=\frac{11.5}{8.9}=\frac{55}{72}\)
b) \(\frac{5}{23}.\frac{17}{26}+\frac{5}{23}.\frac{9}{26}\)
\(=\frac{5}{23}.\left(\frac{17}{26}+\frac{9}{26}\right)=\frac{5}{23}.1=\frac{5}{23}\)
c) \(\left(\frac{3}{29}-\frac{1}{5}\right).\frac{29}{3}=\frac{3}{29}.\frac{29}{3}-\frac{1}{5}.\frac{29}{3}\)
\(=1-1\frac{14}{15}=\frac{14}{15}\)
Bài 3:
a) x/5 = 2/5
=> x =2
b) -4/x = 20/14 = 10/7
=> -4/x = 10/7
=> x.10 = (-4).7
x.10 = - 28
x= -28 :10
x= -2,8
c) 4/7 = 12/x = 12/ 21
=> 12/x = 12/21
=> x = 21
d) 3/7 = x / 21 = 9/21
=> x/21 = 9/21
=> x= 9
Bài 1 d)
\(1-2+3-4+5-6+...+2013\)
\(=1+\left(-2+3\right)+\left(-4+5\right)+...+\left(-2012+2013\right)\)
\(=1+1+1+...+1\left(1006s\right)\)
\(=1006.1=1006\)