Giải thích các bước giải:
a.$(\dfrac73+3.5):(-\dfrac{25}{6}+\dfrac{22}{7})+0.5$
$=(\dfrac73+\dfrac72):(-\dfrac{175}{42}+\dfrac{132}{42})+\dfrac12$
$=(\dfrac{14}6+\dfrac{21}{6}):\dfrac{-175+132}{42}+\dfrac12$
$=\dfrac{14+21}{6}:\dfrac{-43}{42}+\dfrac12$
$=\dfrac{35}{6}:\dfrac{-43}{42}+\dfrac12$
$=\dfrac{35}{6}\cdot \dfrac{42}{-43}+\dfrac12$
$=-\dfrac{35}{6}\cdot \dfrac{42}{43}+\dfrac12$
$=-\dfrac{35}{6}\cdot \dfrac{42}{43}+\dfrac12$
$=-\dfrac{245}{43}+\dfrac12$
$=-\dfrac{490}{86}+\dfrac{43}{86}$
$=\dfrac{-447}{86}$
b.$\dfrac{28}{7}+(-3.25)-\dfrac{17}{7}+4.55$
$=\dfrac{28}{7}-\dfrac{17}{7}+\left(-3.25\right)+4.55$
$=\dfrac{11}{7}-3.25+4.55$
$=\dfrac{11}{7}+1.3$
$=\dfrac{11}{7}+\dfrac{13}{10}$
$=\dfrac{110}{70}+\dfrac{91}{70}$
$=\dfrac{110+91}{70}$
$=\dfrac{201}{70}$
