Question

Thực hiện phép tính sau:

\(A=\dfrac{5}{12.17}+\dfrac{35}{17.18}-\dfrac{39}{18.21}+\dfrac{30}{21.72}\)

Answer 1

tự giải nhé , kcj khó cả , kq là 1/18 nhé

Answer 2

\(\dfrac{5}{12.17}+\dfrac{35}{17.18}-\dfrac{39}{18.21}+\dfrac{30}{21.72}\)

=\(\dfrac{1}{12}-\dfrac{1}{17}+\dfrac{1}{17}+\dfrac{1}{18}-\dfrac{1}{18}-\dfrac{1}{21}+\dfrac{5.6}{21.12.6}\)

= \(\dfrac{1}{12}-\dfrac{1}{21}+\dfrac{5}{21.12}\)

=\(\dfrac{21}{12.21}-\dfrac{12}{12.21}+\dfrac{5}{21.12}\)

= \(\dfrac{21-12+5}{12.21}\)

=\(\dfrac{14}{252}\)

\(=\dfrac{1}{18}\)