Question

a) sắp xếp các phân số sau theo thứ tự từ bé đến lớn:

(1) 6/8; 7/9; 10/12; 11/13; 17/19

(2) 21/23; 3/5; 7/9; 9/10; 1/3; 4/20

Answer 1

(1): \(\dfrac{6}{8}=1-\dfrac{2}{8}\)

\(\dfrac{7}{9}=1-\dfrac{2}{9}\)

\(\dfrac{10}{12}=1-\dfrac{2}{12}\)

\(\dfrac{11}{13}=1-\dfrac{2}{13}\)

\(\dfrac{17}{19}=1-\dfrac{2}{19}\)

8<9<12<13<19

=>\(\dfrac{2}{8}>\dfrac{2}{9}>\dfrac{2}{12}>\dfrac{2}{13}>\dfrac{2}{19}\)

=>\(-\dfrac{2}{8}< -\dfrac{2}{9}< -\dfrac{2}{12}< -\dfrac{2}{13}< -\dfrac{2}{19}\)

=>\(-\dfrac{2}{8}+1< -\dfrac{2}{9}+1< -\dfrac{2}{12}+1< -\dfrac{2}{13}+1< -\dfrac{2}{19}+1\)

=>\(\dfrac{6}{8}< \dfrac{7}{9}< \dfrac{10}{12}< \dfrac{11}{13}< \dfrac{17}{19}\)

 

Answer 2

Bạn lấy tử chia mẫu r sắp xếp thôi nha