Đáp án:
a) $\frac{44}{189}$
b) $\frac{-12}{23}$
c) $\frac{-3}{7}$
d) $\frac{1}{10}$
e) $\frac{20}{3}$
Giải thích các bước giải:
a) $\frac{1}{2}$ ( $\frac{2}{9}$ + $\frac{3}{7}$ - $\frac{5}{27}$ )
= $\frac{1}{2}$ ( $\frac{2.21}{9.21}$ + $\frac{3.27}{7.27}$ - $\frac{5.7}{27.7}$ )
= $\frac{1}{2}$ ($\frac{42}{189}$ + $\frac{81}{189}$ -$\frac{35}{189}$ )
= $\frac{1}{2}$ . $\frac{88}{189}$
= $\frac{44}{189}$
b) ( $\frac{-5}{28}$ + 1,75 +$\frac{8}{35}$ ):( -3$\frac{9}{20}$ )
=( $\frac{-5}{28}$ + $\frac{175}{100}$ +$\frac{8}{35}$ ) : $\frac{-69}{20}$
=( $\frac{-5.25}{28.25}$ + $\frac{175.7}{100.7}$ + $\frac{8.20}{35.20}$ ). $\frac{-20}{69}$
=( $\frac{-125}{700}$ + $\frac{1225}{700}$ + $\frac{160}{700}$ ). $\frac{-20}{69}$
= $\frac{1260}{700}$ . $\frac{-20}{69}$
= $\frac{1260}{35}$ . $\frac{-1}{69}$
= $\frac{-1260}{2415}$
= $\frac{-12}{23}$
c) $\frac{1}{3}$ . $\frac{5}{7}$ -$\frac{7}{27}$ . $\frac{36}{14}$
= $\frac{1}{3}$ . $\frac{5}{7}$ - $\frac{7.1}{3.9}$ . $\frac{36}{14}$
= $\frac{1}{3}$ . $\frac{5}{7}$ - $\frac{1}{3}$ . $\frac{7}{9}$ . $\frac{36}{14}$
= $\frac{1}{3}$ . $\frac{5}{7}$ - $\frac{1}{3}$ . 2
= $\frac{1}{3}$ . ( $\frac{5}{7}$ -2 )
= $\frac{1}{3}$ . ( $\frac{5}{7}$ - $\frac{2.7}{7}$
= $\frac{1}{3}$ . ( $\frac{5}{7}$ - $\frac{14}{7}$ )
= $\frac{1}{3}$ . $\frac{-9}{7}$
= $\frac{-3}{7}$
d) 70,5-528 : $\frac{15}{2}$
= 70,5-528 . $\frac{2}{15}$
= $\frac{705}{10}$ - $\frac{1056}{15}$
= $\frac{705.3}{10.3}$ - $\frac{1056.2}{15.2}$
= $\frac{2115}{30}$ - $\frac{2112}{30}$
= $\frac{3}{30}$
= $\frac{1}{10}$
e) 6,75+ $\frac{1}{4}$ - $\frac{1}{3}$
= $\frac{675}{100}$ + $\frac{1}{4}$ - $\frac{1}{3}$
= $\frac{675.3}{100.3}$ + $\frac{75}{4.75}$ - $\frac{100}{3.100}$
= $\frac{2025}{300}$ + $\frac{75}{100}$ - $\frac{100}{300}$
= $\frac{2000}{300}$
= $\frac{20}{3}$
câu còn lại tự làm nhé vì máy mình hết pin
thông cảm cho mình nha 😅😅
