Bài 1
a) \(MSC=63\)
\(\dfrac{5}{7}=\dfrac{5\times9}{7\times9}=\dfrac{45}{63}\)
\(\dfrac{4}{9}=\dfrac{4\times7}{9\times7}=\dfrac{28}{63}\)
b) MSC = 15
\(\dfrac{5}{3}=\dfrac{5\times5}{3\times5}=\dfrac{25}{15}\)
\(\dfrac{7}{15}\)
c) MSC = 12
\(\dfrac{1}{3}=\dfrac{1\times4}{3\times4}=\dfrac{4}{12}\)
\(\dfrac{5}{4}=\dfrac{5\times3}{4\times3}=\dfrac{15}{12}\)
\(\dfrac{10}{12}\)