Bài 1: quy đồng mẫu các p/s sau:
a) \(\dfrac{7}{30}\);\(\dfrac{8}{45}\);\(\dfrac{11}{90}\)
b)\(\dfrac{-4}{5}\);\(\dfrac{1}{6}\);\(\dfrac{-9}{7}\)
c)\(\dfrac{-7}{24}\);\(\dfrac{11}{12}\);\(\dfrac{-23}{36}\)
d) \(\dfrac{17}{30}\);\(\dfrac{-22}{75}\);5
a: 7/30=21/90
8/45=16/90
11/90=11/90
b: -4/5=-168/210
1/6=35/210
-9/7=-270/210
c: -7/24=-21/72
11/12=66/72
-23/36=-46/72
d: 17/30=85/150
-22/75=-44/150
5=750/150