Question

[Newz]

Tính tỉ số \(\frac{A}{B}\) biết :  A = \(\frac{4}{7\cdot31}\)+\(\frac{6}{7\cdot41}\)+\(\frac{9}{10\cdot41}\)+\(\frac{7}{10\cdot57}\)và  B = \(\frac{7}{19\cdot31}\)+ \(\frac{5}{19\cdot43}\) + \(\frac{3}{23\cdot43}\)+ \(\frac{11}{23\cdot57}\)

Answer 1

[Fairy Tail]

A=4/1.31+6/7.41+9/9.41+ 7/10.57

=20/35.31+30/35.41+45/45.41+35/50.57

=5(4/35.31+6/35.41+9/45.41+7/50.57)

=5(1/31-1/35+1/35-1/41+1/41-1/45+1/45-1/50+1/50-1/57)

=5(1/31-1/57)

B thì làm tương tự nhưng nhân với 2=> B=2(1/31-1/57)

=> A/B=5/2

Answer 2

[Fairy Tail]

A/B=5/2