C1: Rút gọn rồi quy đồng mẫu số:
a)\(\frac{-15}{90},\frac{120}{600},\frac{-75}{150}\) b)\(\frac{54}{-90},\frac{-180}{288},\frac{63}{-180}\)
C2:So sánh phân số:
a)\(\frac{-12}{18}va\frac{-21}{35}\) b)\(\frac{34}{153}va\frac{21}{63}\) c)\(\frac{15}{95}va\frac{24}{136}\)