= -3/5 . (5/7 + 3/7 + 6/7)

= -3/5 . 2

= -6/5

\(-\frac{3}{5}.\frac{5}{7}+-\frac{3}{5}.\frac{3}{7}+-\frac{3}{5}.\frac{6}{7}\)

\(=-\frac{3}{5}.\left(\frac{5}{7}+\frac{3}{7}+\frac{6}{7}\right)\)

\(=-\frac{3}{5}.2\)

\(=-\frac{6}{5}\)

hk tốt ~

\(-\frac{3}{5}.\frac{5}{7}+\left(-\frac{3}{5}\right).\frac{3}{7}+\left(-\frac{3}{5}\right).\frac{6}{7}\)

\(\Leftrightarrow\frac{-3}{5}.\left(\frac{5}{7}+\frac{3}{7}+\frac{6}{7}\right)=-\frac{3}{5}.\frac{14}{7}=-\frac{6}{5}\)

hhgggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggggg

\(\left(24\%+\dfrac{3}{4}+0,76+25\%\right)\times\left(\dfrac{3}{\dfrac{5}{7}}+\dfrac{1}{\dfrac{8}{28}}\right)\)

\(=\left(0,24 +0,75+0,76+0,25\right)\times\left(4,2+10,5\right)\)

\(=\left[\left(0,24+0,76\right)+\left(0,75+0,25\right)\right]\times\left(4,2+10,5\right)\)

\(=\left[1+1\right]\times\left(4,2+10,5\right)\)

\(=2\times14,7=29,4\)

\(~HT~,#Ng\)

ta tách : 1,5 * ( 2/3*5 +2/5*7+.........+2/47*49)                                                                                                                                                          1,5*( 1/3-1/5+1/5-1/7 +.............+1/47-1/49)                                                                                                                                                1,5*( 1/3 -1/49) =1,5* 46/147=23/49     

\(A=\left(7-\frac{3}{4}+\frac{1}{3}\right)-\left(-6+\frac{5}{4}-\frac{4}{3}\right)-\left(13-\frac{7}{4}+\frac{5}{3}\right)\)

\(A=7-\frac{3}{4}+\frac{1}{3}+6-\frac{5}{4}+\frac{4}{3}-13+\frac{7}{4}-\frac{5}{3}\)

\(A=\left(7+6-13\right)+\left(-\frac{3}{4}-\frac{5}{4}+\frac{7}{4}\right)+\left(\frac{1}{3}+\frac{4}{3}-\frac{5}{3}\right)\)

\(A=0-\frac{1}{4}+0=-\frac{1}{4}\)

Nếu có sai sót mong bn thông cảm nha 

=[(1009-1):2+1] x (1009+1):2 x [579-579]

=505 x 505 x 0

=505 x 0

=0

chúc bạn học tốt nha

ủng hộ mk nha

[1+3+3+5+7+....+1009] x [579-579]

[1+3+3+5+7+...+1009] x 0=0

( 1 + 3 + 3 + 5 + 7 + ... + 1009)  x ( 4053 : 7 - 579 )

= ( 1 + 3 + 3 + 5 + 7 + ... + 1009 ) x ( 579 - 579 )

= ( 1 + 3 + 3 + 5 + 7 + ... + 1009 ) x 0

= 0