Tìm \(\displaystyle x\) :
a) \(\displaystyle {4 \over 7}\times x= {1 \over 3}\) b) \(\displaystyle x:{2 \over 5}={2 \over 9}\)
a) \(\displaystyle {4 \over 7}\times x= {1 \over 3}\)
\(\displaystyle x = {1 \over 3}:{4 \over 7}\)
\(\displaystyle x = {1 \over 3} \times {7 \over 4}\)
\(\displaystyle x={7 \over {12}}\)
b) \(\displaystyle x:{2 \over 5}={2 \over 9}\)
\(\displaystyle x={2 \over 9} \times {2 \over 5}\)
\(\displaystyle x={4 \over {45}}\)
-- Mod Toán lớp 4