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A=15x(1/7-1/12-1/98)/18(1/7-1/12-1/98)
A=15/18
A=5/6
h nhe!!!
\(A=\frac{15\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}{18\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}\)
\(A=\frac{15}{18}=\frac{5}{6}\)
\(\frac{15-\frac{15}{7}-\frac{15}{12}-\frac{15}{98}}{18-\frac{18}{7}-\frac{18}{12}-\frac{18}{98}}\)= \(\frac{15-15\left(\frac{1}{7}+\frac{1}{12}+\frac{1}{98}\right)}{18-18\left(\frac{1}{7}+\frac{1}{12}+\frac{1}{98}\right)}\)=\(\frac{15\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}{18\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}\)= \(\frac{15}{18}\)=\(\frac{5}{6}\)
\(\left(\frac{4}{15}-\frac{7}{20}\right):\left(\frac{5}{18}+\frac{11}{12}\right)\)
\(=\left(\frac{16}{60}-\frac{21}{60}\right):\left(\frac{20}{72}+\frac{66}{72}\right)\)
\(=-\frac{1}{12}:\frac{43}{36}=-\frac{1}{12}.\frac{36}{43}=-\frac{3}{43}\)
\(\left[\frac{16}{60}-\frac{21}{60}\right]:\left[\frac{10}{36}+\frac{33}{36}\right]=-\frac{1}{12}:\frac{43}{36}=\frac{\left(-1\right).36}{12.43}=\frac{\left(-1\right).3}{1.43}=-\frac{3}{43}\)
\(15-\frac{15}{7}-\frac{15}{12}-\frac{1}{98}\)
\(=15\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)\)
\(=15x\frac{449}{588}=\frac{2245}{196}\)
\(18-\frac{18}{7}-\frac{18}{12}-\frac{18}{98}\)
\(=18\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)\)
\(=18x\frac{449}{588}=\frac{1347}{98}\)
\(A=\frac{15\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}{18\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{18}\right)}=\frac{15}{18}\)
\(A=\frac{15\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}{18\left(1-\frac{1}{7}-\frac{1}{12}-\frac{1}{98}\right)}=\frac{15}{18}=\frac{5}{6}\)