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\(-\frac{3}{10}-0,125+\frac{-7}{10}+1,125\)
\(=\left(-\frac{3}{10}-\frac{7}{10}\right)+1,125-0,125\)
\(=-\frac{10}{10}+1=-1+1=0\)
Bài làm :
\(\text{a)}=2,5-1,65.\frac{10}{11}=2,5-1.5=1\)
\(b\text{)}=\frac{8-5}{5.8}+\frac{11-8}{8.11}+...+\frac{2015-2012}{2012.2015}\)
\(=\frac{1}{5}-\frac{1}{8}+\frac{1}{8}-\frac{1}{11}+\frac{1}{11}-...+\frac{1}{2012}-\frac{1}{2015}\)
\(=\frac{1}{5}-\frac{1}{2015}\)
\(=\frac{402}{2015}\)
\(a,\frac{5}{16}:0,125-\left(2\frac{1}{4}-0,6\right).\frac{10}{11}\)
\(=\frac{5}{16}:\frac{1}{8}-\left(\frac{9}{4}-\frac{3}{5}\right).\frac{10}{11}\)
\(=\frac{5}{2}-\frac{33}{20}.\frac{10}{11}\)
\(=\frac{5}{2}-\frac{3}{2}=\frac{2}{2}=1\)
a,=\(\frac{1}{2}\)
b,-80000
c,\(\frac{1}{16}\)
d,\(1,271734748x10^{29}\)
Câu a:
(0,25)\(^3\).32
= (0,25)\(^3\).4\(^2\).2
= (0,25.4)\(^2\).(0,25.2)
= 1\(^2\).0,5
= 0,5
Câu b:
(-0,125)\(^3\).(80)\(^4\)
= (-0,125.80)\(^3\) .(80)
= -10\(^3\).80
= -80000
\(=\frac{\left(-1\right)^7}{3^7}.3^7+\left(\frac{1}{8}\right)^3.8^3+\left(\frac{1}{5}\right)^3.\left(2.5\right)^3\)
\(=\left(-1\right)^7+\frac{1^3}{8^3}.8^3+\frac{1^3}{5^3}.2^3.5^3\)
\(=-1+1+2^3=2^3=8\)
a ) \(\left(-\frac{40}{52}.0,32.\frac{17}{20}\right):\frac{64}{75}\)
= \(\left(-\frac{16}{65}.\frac{17}{20}\right):\frac{64}{75}\)
= \(\left(-\frac{68}{325}\right):\frac{64}{75}\)
= \(\frac{-51}{208}\)
b ) \(-\frac{10}{11}.\frac{8}{9}+\frac{7}{18}.\frac{10}{11}\)
= \(\frac{10}{11}.\left(-\frac{8}{9}+\frac{7}{18}\right)\)
= \(\frac{10}{11}.\left(-\frac{1}{2}\right)\)
= \(\frac{-5}{11}\)
c ) \(\frac{45^{10}.5^{20}}{75^{15}}\)
= \(\frac{5^{10}.3^{20}.5^{20}}{5^{30}.3^{15}}\)
= \(\frac{5^{30}.3^{20}}{5^{30}.3^{15}}\)
= 3 5
= 243
d ) ( - 0,125 ) 3 . 80 4
= -80000
Ta có: \(A=\frac{\frac{3}{11}+1-\frac{3}{7}}{3+\frac{9}{11}-\frac{9}{7}}-\frac{\frac{1}{3}+0,25-\frac{1}{5}+0,125}{\frac{7}{6}+\frac{7}{8}-0,7+\frac{7}{16}}\)
\(=\frac{3\left(\frac{1}{11}+\frac{1}{3}-\frac{1}{7}\right)}{9\left(\frac{1}{3}+\frac{1}{11}-\frac{1}{7}\right)}-\frac{2\left(\frac{1}{6}+\frac{1}{8}-\frac{1}{10}+\frac{1}{16}\right)}{7\left(\frac{1}{6}+\frac{1}{8}-\frac{1}{10}+\frac{1}{16}\right)}\)
\(=\frac{3}{9}-\frac{2}{7}=\frac{1}{3}-\frac{2}{7}=\frac{7}{21}-\frac{6}{21}=\frac{1}{21}\)
Vậy \(A=\frac{1}{21}\)
Ta có \(\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}=\left(\frac{3}{10}-\frac{6}{20}-\frac{4}{15}-\frac{1}{20}\right).\frac{5}{19}=-\left(\frac{4}{15}+\frac{1}{20}\right).\frac{5}{19}\)
\(=-\frac{1}{5}\left(\frac{4}{3}+\frac{1}{4}\right).\frac{5}{19}=-\left(\frac{4}{3}+\frac{1}{4}\right).\frac{1}{19}=-\frac{19}{12}.\frac{1}{19}=-\frac{1}{12}\)
Lại có \(\left(\frac{1}{14}+\frac{1}{7}-\frac{3}{35}\right).\frac{-4}{3}=\left(\frac{1}{14}+\frac{1}{7}-\frac{5}{35}+\frac{2}{35}\right).\frac{-4}{3}=\left(\frac{1}{14}+\frac{2}{35}\right).\frac{-4}{3}\)
\(=\frac{1}{7}\left(\frac{1}{2}+\frac{2}{5}\right).\frac{-4}{3}=\left(\frac{1}{2}+\frac{2}{5}\right).\frac{-4}{21}=\frac{7}{10}.\frac{-4}{21}=\frac{-2}{15}\)
Khi đó \(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{3}{35}\right).\frac{-4}{3}}=\frac{\frac{1}{12}}{-\frac{2}{15}}=-\frac{5}{8}\)
Làm lại :
\(\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{35}\right).\left(-\frac{4}{3}\right)=\left(\frac{1}{14}+\frac{1}{7}-\frac{5}{35}+\frac{2}{35}\right)\left(-\frac{4}{3}\right)=\left(\frac{1}{14}+\frac{2}{35}\right)\left(-\frac{4}{3}\right)\)
\(=\frac{1}{7}\left(\frac{1}{2}+\frac{2}{5}\right).\frac{-4}{3}=\frac{-4}{21}.\frac{9}{10}=\frac{-6}{35}\)
Khi đó A = \(\frac{\left(\frac{3}{10}-\frac{4}{15}-\frac{7}{20}\right).\frac{5}{19}}{\left(\frac{1}{14}+\frac{1}{7}-\frac{-3}{35}\right).\frac{-4}{3}}=\frac{-\frac{1}{12}}{-\frac{6}{35}}=\frac{35}{72}\)
\(a.15+\left(-0,125\right)\cdot80=15-10=5\)
\(b.-\frac{3}{10}-0,125+\left(-\frac{7}{10}\right)+1,125\)
\(=\left\lbrack\left(-\frac{3}{10}\right)+\left(-\frac{7}{10}\right)\right\rbrack+\left(1,125-0,125\right)\)
\(=-1+1=0\)
a: Ta có: \(15+\left(-0,125\right)\cdot80\)
\(=15+\frac{-1}{8}\cdot80\)
=15-10
=5
b: \(-\frac{3}{10}-0,125-\frac{7}{10}+1,125\)
\(=\left(-\frac{3}{10}-\frac{7}{10}\right)+\left(1,125-0,125\right)\)
\(=-\frac{10}{10}+1=-1+1=0\)