Tìm y,biết:
a,\(y-\frac{1}{3}=\frac{10}{21}\div\frac{15}{28}\)
b,\(\frac{2}{7}\div y=\frac{10}{21}\times\frac{9}{14}\)
tính bằng cách thuận tiện
a. \(\frac{1}{2}\times\frac{2}{3}\div\frac{4}{3}\times\frac{4}{5}\div\frac{6}{5}\times\frac{6}{7}\div\frac{7}{8}\times\frac{8}{9}\div\frac{10}{9}\)
b.\(\frac{27}{49}\times\frac{49}{50}\times\frac{15}{51}\times(\frac{5}{10}-\frac{1}{2})\)
(7x6=5+2+6x7) =
Tính.
a) $\frac{7}{9} \times \frac{{15}}{{28}} \times \frac{9}{7}$
b) $\frac{9}{{32}} \times \left( {\frac{2}{3} \times \frac{{14}}{{21}}} \right)$
a) $\frac{7}{9} \times \frac{{15}}{{28}} \times \frac{9}{7} = (\frac{7}{9} \times \frac{9}{7}) \times \frac{{15}}{{28}} = 1 \times \frac{{15}}{{28}} = \frac{{15}}{{28}}$
b) $\frac{9}{{32}} \times \left( {\frac{2}{3} \times \frac{{14}}{{21}}} \right) = \frac{9}{{32}} \times \left( {\frac{2}{3} \times \frac{2}{3}} \right) = \frac{9}{{32}} \times \frac{4}{9} = \frac{{36}}{{288}} = \frac{1}{8}$
tìm\(x\in z\)biết :
a.\(\frac{13}{15}-\left(\frac{13}{21}+x\right)\times\frac{7}{12}=\frac{7}{10}\)
b.\(\left(x+\frac{1}{4}-\frac{1}{3}\right)\div\left(2+\frac{1}{6}-\frac{1}{4}\right)=\frac{7}{46}\)
Tìm y \(y+y\times\frac{1}{3}\div\frac{2}{9}+y\div\frac{2}{7}=252\)
\(y+y\times\frac{1}{3}\div\frac{2}{9}+y\div\frac{2}{7}=252\)
\(3y\times\frac{1}{3}\div\frac{2}{9}\div\frac{2}{7}=252\)
\(3y\times\frac{21}{4}=252\)
\(3y=252\div\frac{21}{4}\)
\(3y=48\)
\(y=48\div3\)
\(y=16\)
Tìm x, biết:
\(x=\left(2-\frac{5}{3}+\frac{7}{6}-\frac{9}{10}+\frac{11}{15}-\frac{13}{21}+\frac{15}{28}-\frac{17}{36}+\frac{19}{45}\right)\times\frac{5}{3}\)
Tính : a) \(\frac{1}{9}\div\frac{8}{27}\times-3\div\frac{81}{128}\)
b) \(\frac{\left(13\frac{1}{4}-2\frac{5}{27}-10\frac{5}{6}\right)\times230\frac{1}{25}+46\frac{3}{4}}{\left(1\frac{3}{7}+\frac{10}{3}\right)\div\left(12\frac{1}{3}-14\frac{2}{7}\right)}\)
\(\frac{1}{3}\times\frac{2}{5}\times\frac{3}{7}\times\frac{4}{9}\times\frac{5}{11}\times\frac{6}{15}\times\frac{7}{15}\times\frac{8}{15}\times\frac{9}{19}\times\frac{10}{21}\times\frac{11}{32}\times\frac{12}{25}\times\left\{\frac{126}{252}-\frac{2}{4}\right\}\)
Để nhân các phân số này, ta chỉ cần nhân tử số với nhau và mẫu số với nhau:
\[
\frac{1}{3} \times \frac{2}{5} \times \frac{3}{7} \times \frac{4}{9} \times \frac{5}{11} \times \frac{6}{15} \times \frac{7}{15} \times \frac{8}{15} \times \frac{9}{19} \times \frac{10}{21} \times \frac{11}{32} \times \frac{12}{25} \times \left( \frac{126}{252} - 4 \right)
\]
Sau đó, ta thực hiện các phép tính:
1. Nhân tử số:
\[1 \times 2 \times 3 \times 4 \times 5 \times 6 \times 7 \times 8 \times 9 \times 10 \times 11 \times 12 \times 126 = 997920\]
2. Nhân mẫu số:
\[3 \times 5 \times 7 \times 9 \times 11 \times 15 \times 15 \times 15 \times 19 \times 21 \times 32 \times 25 \times 252 = 7621237680\]
Kết quả là:
\[\frac{997920}{7621237680}\]
Bây giờ, ta có thể rút gọn phân số này bằng cách chia tử số và mẫu số cho 160:
\[ \frac{997920}{7621237680} = \frac{997920 ÷ 160}{7621237680 ÷ 160} = \frac{6237}{47695230} \]
tính nhanh:
\(\frac{10-1\frac{1}{6}\times\frac{6}{7}}{21\div\frac{11}{2}+5\frac{2}{12}}\)
NUGRUGJG T 0U3O UKWI FU JR HKLYG QIQUTMVMNUCNREFDK4NMBNNCBRT 32C489898989 ROUH
Bài làm
\(\frac{10-1\frac{1}{6}\times\frac{6}{7}}{21:\frac{11}{2}+5\frac{2}{12}}\)
\(=\frac{10-\frac{7}{6}\times\frac{6}{7}}{21\times\frac{2}{11}+\frac{62}{12}}\)
\(=\frac{10-1}{\frac{42}{11}+\frac{62}{12}}\)
\(=9:(\frac{42}{11}+\frac{62}{12})\)
\(=9:\left(\frac{504}{132}+\frac{682}{132}\right)\)
\(=9:\frac{1186}{132}\)
\(=9:\frac{593}{66}\)
\(=9\times\frac{66}{593}\)
\(=\frac{594}{593}\)
# Hông bt có đúng k nx. #
Tính giá trị biểu thức
\(1.A=\frac{1}{5}+\frac{3}{17}-\frac{4}{3}+\left(\frac{4}{5}-\frac{3}{17}+\frac{1}{3}\right)-\frac{1}{7}+\left[\frac{-14}{30}\right]\)
\(2.B=\left(\frac{5}{8}-\frac{4}{12}+\frac{3}{2}\right)-\left(\frac{5}{8}+\frac{9}{13}\right)-\left[\frac{-3}{2}\right]+\frac{7}{-15}\)
\(3.C=\frac{5}{18}+\frac{8}{19}-\frac{7}{21}+\left(\frac{-10}{36}+\frac{11}{19}+\frac{1}{3}\right)-\frac{5}{8}\)
\(4.D=\frac{1}{9}-\left[\frac{-5}{23}\right]-\left(\frac{-5}{23}+\frac{1}{9}+\frac{25}{7}\right)+\frac{50}{14}-\frac{7}{30}\)
\(5.E=\frac{1}{13}+\left(\frac{-5}{18}-\frac{1}{13}+\frac{12}{17}\right)+\left(\frac{12}{17}+\frac{5}{18}+\frac{7}{5}\right)\)
\(6.F=\frac{15}{14}-\left(\frac{17}{23}-\frac{80}{87}+\frac{5}{4}\right)+\left(\frac{12}{17}-\frac{15}{14}+\frac{1}{4}\right)\)
\(7.G=\frac{1}{25}-\frac{4}{27}+\left(\frac{-23}{27}+\frac{-1}{25}-\frac{5}{43}\right)+\frac{5}{43}-\frac{4}{7}\)
\(8.H=\frac{4}{15}-\frac{23}{28}-\left(\frac{-23}{28}+\frac{-11}{15}-\frac{29}{27}\right)-\frac{2}{27}\)
\(9.K=\frac{1}{16}-\frac{5}{21}+\left(\frac{-1}{16}+\frac{-3}{5}-\frac{-5}{21}\right)+\frac{-2}{5}+\frac{3}{4}\)
\(10.L=\frac{7}{12}+\frac{15}{14}-\left(\frac{14}{22}+\frac{-1}{14}+\frac{5}{21}\right)-\frac{-5}{21}+\frac{3}{5}\)
yutyugubhujyikiu