Đáp án:
Giải thích các bước giải:
$1)A=\dfrac{5}{13}+\dfrac{5}{7}+\dfrac{-20}{41}+\dfrac{8}{12}+\dfrac{-21}{41}$
$=\dfrac{5}{13}+\dfrac{8}{13}+\dfrac{-20}{41}+\dfrac{-21}{41}+\dfrac{5}{7}$
$=1+(-1)+\dfrac{5}{7}$
$=\dfrac{5}{7}$
$B=\dfrac{5}{7}.\dfrac{2}{11}+\dfrac{5}{7}.\dfrac{12}{11}-\dfrac{5}{7}.\dfrac{7}{11}$
$=\dfrac{5}{7}.\left (\dfrac{2}{11}+\dfrac{12}{11}-\dfrac{7}{11} \right )$
$=\dfrac{5}{7}.\dfrac{7}{11}$
$=\dfrac{5}{11}$
$G=\dfrac{-2}{3}+\dfrac{-5}{7}+\dfrac{2}{3}+\dfrac{-2}{7}$
$=\dfrac{-2}{3}+\dfrac{2}{3}+\dfrac{-5}{7}+\dfrac{-2}{7}$
$=0+(-1)=-1$
$H=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}.\dfrac{9}{11}$
$=\dfrac{-5}{7}.\left (\dfrac{2}{11}+\dfrac{9}{11} \right )$
$=\dfrac{-5}{7}.1=\dfrac{-5}{7}$
$N=\dfrac{-5}{13}+\dfrac{5}{7}+\dfrac{20}{41}+\dfrac{-8}{13}+\dfrac{21}{41}$
$=\dfrac{-5}{13}+\dfrac{-8}{13}+\dfrac{20}{41}+\dfrac{21}{41}+\dfrac{5}{7}$
$=-1+1+\dfrac{5}{7}$
$=\dfrac{5}{7}$
$E=\dfrac{5}{7}.\dfrac{2}{11}+\dfrac{5}{7}.\dfrac{12}{11}-\dfrac{5}{7}.\dfrac{7}{11}$
$=\dfrac{5}{7}.\left (\dfrac{2}{11}+\dfrac{12}{11}-\dfrac{7}{11} \right )$
$=\dfrac{5}{7}.\dfrac{7}{11}$
$=\dfrac{5}{11}$
