a: \(=\dfrac{-4}{9}\left(\dfrac{7}{15}+\dfrac{8}{15}\right)=\dfrac{-4}{9}\)
b: \(=\dfrac{-5}{4}\left(\dfrac{16}{25}+\dfrac{9}{25}\right)=\dfrac{-5}{4}\)
c: \(=\left(4+\dfrac{11}{23}+2+\dfrac{12}{23}\right)-\dfrac{9}{14}-\dfrac{5}{4}\)
\(=7-\dfrac{9}{14}-\dfrac{5}{4}=\dfrac{143}{28}\)
d: \(=\left(2+\dfrac{13}{27}+3+\dfrac{14}{27}\right)-\left(\dfrac{7}{15}+\dfrac{8}{15}\right)\)
=5+1-1
=5
e: \(=11+\dfrac{1}{4}-2-\dfrac{5}{7}-5-\dfrac{1}{4}=4-\dfrac{5}{7}=\dfrac{23}{7}\)
g: \(=\dfrac{7}{19}\left(\dfrac{8}{11}+\dfrac{3}{11}\right)+\dfrac{12}{19}=\dfrac{7}{19}+\dfrac{12}{19}=1\)
\(a)-4/9*(7/15+8/15)=-4/9*1=-4/9\)
\(b)-5/4*(16/25+9/25)=-5/4*1=-5/4\)
Những câu sau làm tương tự nhé, chúc em học giỏi