=-3/26(-15/29-2/19)

=-3/26*(-17/19)

=3/26*17/19

=51/494

\(-\dfrac{3}{26}.\left(-\dfrac{15}{19}\right)-\dfrac{2}{19}.\left(-\dfrac{3}{26}\right)\)

\(=-\dfrac{3}{26}.\text{[}\left(-\dfrac{15}{19}-\dfrac{2}{19}\right)\)

\(=-\dfrac{3}{26}.\left(-\dfrac{17}{19}\right)\)

=\(\dfrac{51}{494}\)

ghép cặp vào ra 28 nha

Bằng 28.

Vậy mà cũng ko biết

=26(17+19*2+44+1)

=26*100

=2600

\(d,-\dfrac{3}{26}.\left(-\dfrac{15}{19}\right)+\dfrac{2}{19}.\left(-\dfrac{3}{26}\right)\\=-\dfrac{3}{26}.\left(-\dfrac{15}{19}+\dfrac{2}{19}\right)\\ =-\dfrac{13}{19}.\left(-\dfrac{3}{26}\right)\\ =\dfrac{3}{38}. \)

d) \(\dfrac{-3}{26}\times\left(\dfrac{-15}{19}\right)+\dfrac{2}{19}\times\dfrac{-3}{26}\)

\(=\dfrac{-3}{26}\times\left[\left(\dfrac{-15}{19}\right)+\dfrac{2}{19}\right]\)

\(=\dfrac{-3}{26}\times\dfrac{-13}{19}\)

\(=\dfrac{3}{38}\)

( 19 + 81 ),26 + 75,(19 + 81 ) - 81 -19

= 100,26 + 75,100 - 81 -19

= 176,36 - 81 - 19

= 94,36 - 19

= 75,36

\(\frac{x-19}{24}\)+ \(\frac{x-19}{25}\)= \(\frac{x-19}{26}\)+ \(\frac{x-19}{27}\)

<=> \(\frac{x-19}{24}\)+ \(\frac{x-19}{25}\)- \(\frac{x-19}{26}\)- \(\frac{x-19}{27}\)= 0 

<=> \(\frac{x}{24}\)- \(\frac{19}{24}\)+ \(\frac{x}{25}\)- \(\frac{19}{25}\)- \(\frac{x}{26}\)+\(\frac{19}{26}\)- \(\frac{x}{27}\)+\(\frac{19}{27}\)= 0 

<=> \(\left(\frac{x}{24}+\frac{x}{25}-\frac{x}{26}-\frac{x}{27}\right)+\left(-\frac{19}{24}-\frac{19}{25}+\frac{19}{26}-\frac{19}{27}\right)=0\)

<=> \(x\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)-19\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)=0\)

<=> \(x\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)\)= \(19\left(\frac{1}{24}+\frac{1}{25}-\frac{1}{26}-\frac{1}{27}\right)\)

<=> x = 19

657892 chia 7896=

Tuyến đường nào không đi từ Duyên hải Nam Trung Bộ qua Tây Nguyên: 

Hồ Chí Minh, 24, 19, 25, 26, 27

Hồ Chí Minh, 14, 24, 19, 25, 26, 27

Hồ Chí Minh, 24, 19, 80, 51

Hồ Chí Minh, 24, 19, 25, 30, 33

= (26/15-7/15):19/45

=\(\dfrac{19}{15}:\dfrac{19}{45}\)

=\(\dfrac{19}{15}x\dfrac{45}{19}=\dfrac{45}{15}=3\)

= ( 26/15 - 7/15 ) : 19/45

= 19/15 : 19/15

=1