Tính `B:` `B=(5/(19.33)+5/(19.43)+3/(23.43)+11/(23.57)+9/(57.33)):(2/39-1/15-2/153)/(1/34+3/20-3/26)`

Đáp án:

$B=\dfrac{-3}{44}.$

Giải thích các bước giải:

$B=\left(\dfrac{5}{19.33}+\dfrac{5}{19.43}+\dfrac{3}{23.43}+\dfrac{11}{23.57}+\dfrac{9}{57.33}\right): \dfrac{\dfrac{2}{39}-\dfrac{1}{15}-\dfrac{2}{153}}{\dfrac{1}{34}+\dfrac{3}{20}-\dfrac{3}{26}}\\ =2\left(\dfrac{5}{33.38}+\dfrac{5}{38.43}+\dfrac{3}{43.46}+\dfrac{11}{46.57}+\dfrac{9}{57.66}\right): \dfrac{-\dfrac{4}{9}\left(-\dfrac{3}{26}+\dfrac{3}{20}+\dfrac{1}{34}\right)}{\dfrac{1}{34}+\dfrac{3}{20}-\dfrac{3}{26}}\\ =2\left(\dfrac{38-33}{33.38}+\dfrac{43-38}{38.43}+\dfrac{46-43}{43.46}+\dfrac{57-46}{46.57}+\dfrac{66-57}{57.66}\right): \dfrac{-4}{9}\\ =\dfrac{1}{2}\left(\dfrac{38}{33.38}-\dfrac{33}{33.38}+\dfrac{43}{38.43}-\dfrac{38}{38.43}+\dfrac{46}{43.46}-\dfrac{43}{43.46}+\dfrac{57}{46.57}-\dfrac{46}{46.57}+\dfrac{66}{57.66}-\dfrac{57}{57.66}\right). \dfrac{-9}{4}\\ =2\left(\dfrac{1}{33}-\dfrac{1}{38}+\dfrac{1}{38}-\dfrac{1}{43}+\dfrac{1}{43}-\dfrac{1}{46}+\dfrac{1}{46}-\dfrac{1}{57}+\dfrac{1}{57}-\dfrac{1}{66}\right). \dfrac{-9}{4}\\ =2. \dfrac{-9}{4}.\left(\dfrac{1}{33}-\dfrac{1}{57}\right)\\ = \dfrac{-9}{2}.\left(\dfrac{1}{33}-\dfrac{1}{66}\right)\\ = \dfrac{-9}{2}.\dfrac{1}{66}\\ = \dfrac{-3}{44}.$