Câu 1 :

A= 1.2.3...9-1.2.3...8-1.2.3...8²

  = 1.2.3...8. ( 9 - 1 - 8 )

  = 1.2.3...8.0

  = 0

\(=\frac{23^{10}\left(1-23\right)}{23^{10}\left(23+21\right)}=\frac{-22}{44}=\frac{-1}{2}\)

\(\frac{23^{10}-23^{11}}{23^{11}+21.23^{10}}\)

\(=\frac{23^{10}.\left(1-23\right)}{23^{10}.\left(23+21\right)}\)

\(=\frac{-22}{44}=\frac{-22}{22.2}=\frac{-1}{2}\)

\(\frac{23^{10}-23^{11}}{23^{11}+21.23^{10}}=\frac{23^{10}\left(1-23\right)}{23^{10}\left(23+21\right)}=-\frac{22}{44}=-\frac{1}{2}\)

mk lam cho

=23¹⁰(1-23)/23¹⁰(23-21)=-22/2=-11

tk nha

b=(11,81+8,19).0,02/9:11,25

b=20.0,02/9:11,25

b=2/45:11,25

b=8/2025

k mk ha

\(B=\left(11,81+8,19\right)\cdot\frac{0,02}{9}:11,25\)

\(B=20\cdot\frac{1}{450}:11,25\)

\(B=\frac{2}{45}:\frac{45}{4}\)

\(B=\frac{2}{45}\cdot\frac{4}{45}\)

\(B=\frac{2\cdot4}{45\cdot45}\)

\(B=\frac{8}{45^2}\)

Vậy\(B=\frac{8}{45^2}\)

~ học tốt ~

= -11/23.-10/13+-11/23.-3/13-(-12/23)

= -11/23.(-10/13+-3/13)-(-12/23)

= -11/23. -1 -(-12/23)

= 11/23- (-12/23)

= -1/23

Ta có: \(A=\dfrac{-11}{23}\cdot\dfrac{-10}{13}+\dfrac{-11}{13}\cdot\dfrac{-3}{23}-\left(-\dfrac{12}{23}\right)\)

\(=\dfrac{11}{13}\left(\dfrac{10}{23}+\dfrac{3}{23}\right)+\dfrac{12}{23}\)

\(=\dfrac{11}{23}\cdot\dfrac{13}{13}+\dfrac{12}{23}\)

\(=\dfrac{-1}{23}\)

-2 và 0 nha bạn

 5/11+16/22+(-12/4) +(-2/11)

       = -2

7/23+(-10/18+(-4/9)+16/23

 = 0

bn quy đồng mẫu số nha

duyệt đi

a) Ta có: \(\dfrac{21}{25}\cdot\dfrac{11}{9}\cdot\dfrac{5}{7}\)

\(=\dfrac{21\cdot11\cdot5}{25\cdot9\cdot7}\)

\(=\dfrac{3\cdot7\cdot11\cdot5}{5\cdot5\cdot3\cdot3\cdot7}\)

\(=\dfrac{11}{5\cdot3}=\dfrac{11}{15}\)

a) 21/25. 11/9. 5/7

=(21/25.5/7).11/9

= 3/5. 11/9

=11/15

b) 5/23 . 17/26 . 5/23 . 9/26

=5/23.( 17/26+9/26)

=5/23. 1

=5/23