Question

Quy đồng mẫu số: 1/3,1/5 và 1/7

Answer 1

Mẫu số chung : \(105\)

\(\dfrac{1}{3}=\dfrac{1.35}{35.3}=\dfrac{35}{105}\\ \dfrac{1}{5}=\dfrac{1.21}{21.5}=\dfrac{21}{105}\\ \dfrac{1}{7}=\dfrac{1.15}{15.7}=\dfrac{15}{105}\)

Answer 2

\(\dfrac{1.5.7}{3.5.7}=\dfrac{35}{105}\)

\(\dfrac{1.3.7}{5.3.7}=\dfrac{21}{105}\)

\(\dfrac{1.3.5}{7.3.5}=\dfrac{15}{105}\)

Answer 3

\(\dfrac{1}{3};\dfrac{1}{5};\dfrac{1}{7}\) MCNN: 105

\(\dfrac{1}{3}=\dfrac{35}{105}\) ; \(\dfrac{1}{5}=\dfrac{21}{105}\) ; \(\dfrac{1}{7}=\dfrac{15}{105}\)

Vậy 3 phân số đã được quy đồng.