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16 tháng 2 2015

c. N= \(\frac{-5}{7}\cdot\left(\frac{2}{11}+\frac{9}{11}\right)+\frac{12}{7}\)

N=1

23 tháng 9 2016

bai de the ma cung hoi

4 tháng 10 2021

yutyugubhujyikiu

17 tháng 12 2016

a) \(\frac{17}{9}-\frac{17}{9}:\left(\frac{7}{3}+\frac{1}{2}\right)\)

= \(\frac{17}{9}-\frac{17}{9}:\frac{17}{6}\)

= \(\frac{17}{9}-\frac{2}{3}\)

= \(\frac{11}{9}\)

b) \(\frac{4}{3}.\frac{2}{5}-\frac{3}{4}.\frac{2}{5}\)

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

= \(\frac{2}{5}.\frac{7}{12}\)

= \(\frac{7}{30}\)

Mình lười làm quá, hay mình nói kết quả cho bn thôi nha

c) -6

d) 3

e) 3

g) 12

h) \(\frac{23}{18}\)

i) \(\frac{-69}{20}\)

k) \(\frac{-1}{2}\)

l) \(\frac{49}{5}\)

18 tháng 12 2016

a) \(\frac{11}{24}-\frac{5}{41}+\frac{13}{24}+0,5-\frac{36}{41}\)

= \(\frac{11}{24}-\frac{5}{41}+\frac{13}{24}+\frac{1}{2}-\frac{36}{41}\)

= \(\frac{1}{2}-\left\{\frac{11}{24}+\frac{13}{24}\right\}-\left\{\frac{5}{41}+\frac{36}{41}\right\}\)

=\(\frac{1}{2}-\frac{24}{24}-\frac{41}{41}\)

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

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

b) \(-12:\left\{\frac{3}{4}-\frac{5}{6}\right\}^2\)

= \(-12:\left\{\frac{9}{12}-\frac{10}{12}\right\}^2\)

= \(-12:\left\{\frac{-1}{12}\right\}^2\)

= \(-12:\frac{1}{144}\)

= \(-12.144\)

= -1728

c) \(\frac{7}{23}.\left[\left(\frac{-8}{6}\right)-\frac{45}{18}\right]\)

= \(\frac{7}{23}.\left[\left(\frac{-24}{18}\right)-\frac{45}{18}\right]\)

= \(\frac{7}{23}.\left(\frac{-23}{6}\right)\)

= \(\frac{-7}{6}\)

d) \(23\frac{1}{4}.\frac{7}{5}-13\frac{1}{4}:\frac{5}{7}\)

= \(23\frac{1}{4}.\frac{7}{5}-13\frac{1}{4}.\frac{7}{5}\)

= \(\left\{23\frac{1}{4}-13\frac{1}{4}\right\}.\frac{7}{5}\)

= \(10.\frac{7}{5}\)

= 14

 

e) (1+2314).(0,834)2

= (1+2314).(\(\frac{4}{5}\)34)2

= \(\left(\frac{12}{12}+\frac{8}{12}-\frac{3}{12}\right).\left(\frac{16}{20}-\frac{15}{20}\right)^2\)

= \(\frac{17}{12}.\left(\frac{1}{20}\right)^2\)

= \(\frac{17}{20}.\frac{1}{400}\)

= \(\frac{17}{8000}\)

 

26 tháng 8 2016

\(\left(\frac{-1}{4}+\frac{7}{33}-\frac{5}{3}\right)-\left(\frac{-5}{4}+\frac{6}{11}-\frac{48}{49}\right)=\left(\frac{-1}{4}-\frac{16}{11}\right)-\left(-\frac{31}{44}-\frac{48}{49}\right)=-\frac{1}{4}-\frac{16}{11}+\frac{31}{44}+\frac{48}{49}=-\frac{1}{49}\)

\(\left(\frac{1}{4}-x\right)\left(x+\frac{2}{5}\right)=0\)

Ta xét 2 trường hợp 

\(\begin{cases}\frac{1}{4}-x=0\\x+\frac{2}{5}=0\end{cases}\Rightarrow\orbr{\begin{cases}x=\frac{1}{4}\\x=-\frac{2}{5}\end{cases}}\)

tớ mới làm bài 1 thôi bài 2 3 tớ ko có thời gian 

a)     \(1\frac{3}{19}+\frac{8}{21}-\frac{3}{19}+0.5+\frac{13}{21}\)

\(=\left(1\frac{3}{19}-\frac{3}{19}\right)+\left(\frac{8}{21}+\frac{13}{21}\right)+0.5\)

\(=1+1+0.5=2.5\)

b)  \(\left(-\frac{3}{4}+\frac{2}{7}\right):\frac{3}{7}+\left(\frac{5}{7}+\frac{-1}{4}\right):\frac{3}{7}\)

\(=\left(\frac{-3}{4}+\frac{2}{7}+\frac{5}{7}+\frac{-1}{4}\right):\frac{3}{7}\)

\(=0:\frac{3}{7}=0\)