\(\frac{-4}{9}.\frac{7}{15}+\frac{4}{-9}.\frac{8}{15}\)

\(\Rightarrow\frac{-4}{9}.\frac{7}{15}+\frac{-4}{9}.\frac{8}{15}\)

\(\Rightarrow\frac{-4}{9}.\left(\frac{7}{15}+\frac{8}{15}\right)\)

\(\Rightarrow\frac{-4}{9}.\frac{15}{15}\)

\(\Rightarrow\frac{-4}{9}.1\)

\(\Rightarrow\frac{-4}{9}\)

\(\frac{-4}{9}.\frac{7}{15}+\frac{4}{-9}.\frac{8}{15}\)

\(=\frac{-4}{9}.\frac{7}{15}+\frac{-4}{9}.\frac{8}{15}\)

\(=\frac{-4}{9}.\left(\frac{7}{15}+\frac{8}{15}\right)\)

\(=\frac{-4}{9}.\frac{15}{15}\)

\(=\frac{-4}{9}.1\)

\(=\frac{-4}{9}\)

=19/18 nha bn

học tốt

=19/18 nha bn

học tốt

câu trả lời đúng là a

\(\dfrac{5}{-4}.\dfrac{16}{25}+\dfrac{4}{-9}.\dfrac{8}{15}=-\dfrac{4}{5}+\left(-\dfrac{32}{135}\right)=-\dfrac{28}{27}\)

\(\dfrac{5}{-4}.\dfrac{16}{25}+\dfrac{4}{-9}.\dfrac{8}{15}=\dfrac{-4}{5}+\dfrac{-32}{135}=\dfrac{-28}{27}\)

Bài làm

     \(\frac{2}{3}.\frac{7}{15}-\frac{2}{3}.\frac{5}{27}\)

\(=\frac{2}{3}.\left(\frac{7}{15}-\frac{5}{27}\right)\)

\(=\frac{2}{3}.\left(\frac{63}{135}-\frac{25}{135}\right)\)

\(=\frac{2}{3}.\frac{38}{135}\)

\(=\frac{76}{405}\)

~ Nếu rút gọn đc rút hộ ~

        \(-\frac{4}{9}.\frac{7}{15}+\frac{4}{9}.\frac{5}{27}\)

\(=-\frac{4}{9}.\frac{7}{15}-\left(-\frac{4}{9}\right).\frac{5}{27}\)

\(=-\frac{4}{9}.\left(\frac{7}{15}-\frac{5}{27}\right)\)

\(=-\frac{4}{9}.\left(\frac{63}{135}-\frac{25}{135}\right)\)

\(=-\frac{4}{9}.\frac{38}{135}\)

\(=\frac{152}{1215}\)

~ Rút gọn đc thì rút ~
# Chúc bạn học tốt #

\(\frac{\frac{2}{3}.\frac{7}{15}-\frac{2}{3}.\frac{5}{27}}{\frac{-4}{9}.\frac{7}{15}+\frac{4}{9}.\frac{5}{27}}=\frac{\frac{2}{3}.\left(\frac{7}{15}-\frac{5}{27}\right)}{\frac{4}{9}\left(\frac{-7}{15}+\frac{5}{27}\right)}=\frac{\frac{2}{3}}{\frac{4}{9}}=\frac{2:3}{4:9}=\frac{2.\frac{1}{3}}{4.\frac{1}{9}}=\frac{1.\frac{1}{3}}{2.\frac{1}{9}}=\frac{1}{6}\)

Bài 1

a, A=5/12.6/11+5/12.5/11+7/12

A=5/12x(6/11+5/11)+7/12

A=5/12x1+7/12

A=12/12=1

Chốc nữa mình lm tp nha

số các số hạng là :

(10-0,1):0,1+1=100

tổng của dãy số trên là :

(0,1+10)x100:2=505