Question

 

  Quy đồng mẫu 7/30; 13/60; -9/40

Answer 1

\(\text{MSC : 120}\)

\(\dfrac{\text{7}}{30}=\dfrac{7\times4}{30\times4}=\dfrac{28}{120}\)

\(\dfrac{\text{13}}{60}=\dfrac{13\times2}{60\times2}=\dfrac{26}{120}\)

\(\dfrac{\text{-9}}{40}=\dfrac{-9\times3}{40\times3}=\dfrac{-27}{120}\)

Answer 2

a) 7/30;13/60;-9/40(MSC=120)

=>7/30= 28/120;13/60=26/120; -9/40=-27/120.