Tìm x biết \[\frac{{\left( {1,16 - x} \right).5,25}}{{\left( {10\frac{5}{9} - 7\frac{1}{4}} \right).2\frac{2}{{17}}}} = 75\% \]

Trả lời:

\[\frac{{\left( {1,16 - x} \right).5,25}}{{\left( {10\frac{5}{9} - 7\frac{1}{4}} \right).2\frac{2}{{17}}}} = 75\% \]

\[\frac{{\left( {\frac{{116}}{{100}} - x} \right).\frac{{525}}{{100}}}}{{\left( {\frac{{95}}{9} - \frac{{29}}{4}} \right).\frac{{36}}{{17}}}} = \frac{{75}}{{100}}\]

\[\frac{{\left( {\frac{{29}}{{25}} - x} \right).\frac{{21}}{4}}}{{\frac{{119}}{{36}}.\frac{{36}}{{17}}}} = \frac{3}{4}\]

\[\frac{{\left( {\frac{{29}}{{25}} - x} \right).\frac{{21}}{4}}}{7} = \frac{3}{4}\]

\[\left( {\frac{{29}}{{25}} - x} \right).\frac{{21}}{4}.4 = 7.3\]

\[\left( {\frac{{29}}{{25}} - x} \right).21 = 21\]

\[\frac{{29}}{{25}} - x = 21:21\]

\[\frac{{29}}{{25}} - x = 1\]

\[x = \frac{{29}}{{25}} - 1\]

\[x = \frac{4}{{25}}\]

Đáp án cần chọn là: C