K
Khách
Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.
Các câu hỏi dưới đây có thể giống với câu hỏi trên
13 tháng 9 2017
a,(11/15+4/15)+(5/7+2/7)
=1+1
=2
b,5/9x(1/2+6/4)
=5/9x2
=10/9
c,1/2:(7/8+9/8)
=1/2:2
=1
d,(17/10-7/10)+1/2
=1+1/2
=3/2
3 tháng 8 2017
(\(\frac{5}{7}-y\)) x \(\frac{14}{5}=\frac{6}{5}\)
\(\frac{5}{7}-y\) = \(\frac{6}{5}:\frac{14}{5}\)
\(\frac{5}{7}-y\) = \(\frac{3}{7}\)
y = \(\frac{5}{7}-\frac{3}{7}\)
y = \(\frac{2}{7}\)
DP
3 tháng 8 2017
\(\left(\frac{5}{7}-y\right)\cdot\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)
\(\Leftrightarrow\left(\frac{5}{7}-y\right)\cdot\frac{14}{5}=\frac{7}{10}+\frac{5}{10}\)
\(\Leftrightarrow\left(\frac{5}{7}-y\right)\cdot\frac{14}{5}=\frac{6}{5}\)
\(\Leftrightarrow\frac{5}{7}-y=\frac{6}{5}\div\frac{14}{5}\)
\(\Leftrightarrow\frac{5}{7}-y=\frac{3}{7}\)
\(\Rightarrow y=\frac{5}{7}-\frac{3}{7}=\frac{2}{7}\)
13 tháng 9 2017
a) \(\frac{11}{15}+\frac{5}{7}+\frac{2}{7}+\frac{4}{15}=\left(\frac{11}{15}+\frac{4}{15}\right)+\left(\frac{5}{7}+\frac{2}{7}\right)\)
\(=2\)
b) \(\frac{5}{9}\times\frac{1}{2}\times\frac{5}{9}\times\frac{6}{4}=\frac{25}{81}\times\frac{3}{4}=\frac{25}{108}\)
c) \(\frac{7}{8}\div\frac{1}{2}+\frac{9}{8}\div\frac{1}{2}=\left(\frac{7}{8}+\frac{9}{8}\right)\div\frac{1}{2}\)
\(=2\div\frac{1}{2}=4\)
d) \(\frac{17}{10}+\frac{1}{2}-\frac{7}{10}=\left(\frac{17}{10}-\frac{7}{10}\right)+\frac{1}{2}\)
\(=1+\frac{1}{2}=\frac{3}{2}\)
HT
13 tháng 9 2017
a) \(\frac{11}{15}+\frac{5}{7}+\frac{2}{7}+\frac{4}{15}\)
\(=\left(\frac{11}{15}+\frac{4}{15}\right)+\left(\frac{5}{7}+\frac{2}{7}\right)\)
\(=1+1\)
\(=2\)
b) \(\frac{5}{9}.\frac{1}{2}.\frac{5}{9}.\frac{6}{4}\)
\(=\left(\frac{5}{9}\right)^2\left(\frac{1}{2}.\frac{6}{4}\right)\)
\(=\frac{25}{81}.\frac{3}{4}\)
\(=\frac{25}{108}\)
c) \(\frac{7}{8}:\frac{1}{2}+\frac{9}{8}:\frac{1}{2}\)
\(=\frac{7}{8}.2+\frac{9}{8}.2\)
\(=2\left(\frac{7}{8}+\frac{9}{8}\right)\)
\(=2.\frac{16}{8}\)
\(=2.2\)
\(=4\)
d) \(\frac{17}{10}+\frac{1}{2}-\frac{7}{10}\)
\(=\left(\frac{17}{10}-\frac{7}{10}\right)+\frac{1}{2}\)
\(=1+\frac{1}{2}\)
\(=\frac{2}{2}+\frac{1}{2}\)
\(=\frac{3}{2}\)
KN
20 tháng 2 2019
\(x+x\times\frac{1}{3}\div\frac{2}{9}+x\div\frac{2}{7}=252\)
\(\Leftrightarrow x+x\times\frac{1}{3}\times\frac{9}{2}+x\times\frac{7}{2}=252\)
\(\Leftrightarrow x\left(1+\frac{1}{3}\times\frac{9}{2}+\frac{7}{2}\right)=252\)
\(\Leftrightarrow x\left(\frac{6}{6}+\frac{9}{6}+\frac{21}{6}\right)=252\)
\(\Leftrightarrow x\times\frac{36}{6}=252\)
\(\Leftrightarrow x\times6=252\)
\(\Leftrightarrow x=252\div6\)
\(\Leftrightarrow x=43\)
TL
1
IA
9 tháng 6 2018
\(\Leftrightarrow10\times\left(\frac{1}{1\times2}+\frac{1}{2\times3}+...+\frac{1}{x\times\left(x+1\right)}\right)=9\)
\(\Leftrightarrow\left(\frac{1}{1}-\frac{1}{2}+\frac{1}{2}-\frac{1}{3}+...+\frac{1}{x}-\frac{1}{x+1}\right)=9\div10\)
\(\Leftrightarrow\frac{1}{1}-\frac{1}{x+1}=\frac{9}{10}\)
\(\Leftrightarrow\frac{1}{x+1}=1-\frac{9}{10}\)
\(\Leftrightarrow\frac{1}{x+1}=\frac{1}{10}\)
\(\Rightarrow x+1=10\)
\(\Leftrightarrow x=9\)
Vậy x = 9
7 tháng 8 2017
\(\left(\frac{5}{7}-y\right)x\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)
\(\left(\frac{5}{7}-y\right)x\frac{14}{5}=\frac{6}{5}\)
\(\frac{5}{7}-y=\frac{6}{5}:\frac{14}{5}\)
\(\frac{5}{7}-y=\frac{3}{7}\)
Y = \(\frac{5}{7}-\frac{3}{7}\)
Y = \(\frac{2}{7}\)
7 tháng 8 2017
\(\left(\frac{5}{7}-y\right).\frac{14}{5}=\frac{7}{10}+\frac{1}{2}\)
\(\left(\frac{5}{7}-y\right).\frac{14}{5}=\frac{6}{5}\)
\(\frac{5}{7}-y=\frac{6}{5}\div\frac{14}{5}\)
\(\frac{5}{7}-y=\frac{3}{7}\)
\(y=\frac{5}{7}-\frac{3}{7}\)
\(y=\frac{2}{7}\)
\(\frac{1}{7}:q=\frac{9}{10}\)
\(q=\frac{1}{7}:\frac{9}{10}\)
\(q=\frac{10}{63}\)
#munpkutkuy
#study well :3
1/7 : q = 9/10
q = 1/7:9/10
q =10/63
nếu đúng thì