Tìm y:
a) \(\displaystyle y + {3 \over 4} = {4 \over 5}\) b) \(\displaystyle y - {3 \over {11}} = {9 \over {22}}\) c) \(\displaystyle {9 \over 2} - y = {2 \over 9}\)
\( \displaystyle a)\,\,y + {3 \over 4} = {4 \over 5} \\ \displaystyle y = \,\,{4 \over 5} - {3 \over 4} \\ \displaystyle y = \,\,{1 \over {20}} \)
\( \displaystyle b)\,\,y - {3 \over {11}} = {9 \over {22}} \\ \displaystyle y = {9 \over {22}} + {3 \over {11}} \\ \displaystyle y = {{15} \over {22}}\)
\(\displaystyle c)\,\,{9 \over 2} - y = {2 \over 9} \\ \displaystyle y = {9 \over 2} - {2 \over 9} \\ \displaystyle y = {{77} \over {18}} \)
-- Mod Toán lớp 4