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ko hiểu tự làm đuy đi ám Phong 

nên xem nội quy khi đặt câu hỏi nếu ko muốn bị bay cái acc của bạn!

a ) 21/11 * 22/ 17 *68 / 63 = 42 /17 * 68 / 63 = 8 / 3

b) 5 / 14 * 7 / 13 * 26 / 25 = 5/ 26 * 26 / 25 = 1/ 5

Bố con ngố

Đ là bài phân số à bn !? 

a,= ( 1/14 + 13/14 ) + ( 4/11 + 14/22 )

   =         1               +             1

   =  2

b, = ( 2/26 + 12/13 ) + (3/4 + 25/100 ) + ( 4/7 + 9/21)

    =      1                  +            1             +         1

    =   3

thanks !!!

a, 7/12 - 3/4 . 5/6 

= 7/12 - 5/8

= 14/24- 15/24

= -1/24

b,( 2/1/3 + 1/3/4 ) . 12/13

= ( 6/3 + 7/3 ) . 12/13

= 13/3 . 12/13

=4

c, 12 : ( 3/4 -5/6 ) . 2

= 12 : ( -1/12 ) .2

= 12 . -12 . 2

= -228

d, 7/22 : 3/11 + 7/22 : 4/11 

= 7/22 . 11/3 + 7/22 . 11/4

= 7/22 . ( 11/3 + 11/4 )

....

tiếp theo bạn tự làm nhé!

\(A=\dfrac{5}{11}.\dfrac{5}{7}+\dfrac{5}{11}.\dfrac{2}{7}+\dfrac{6}{11}=\dfrac{5}{11}\left(\dfrac{5}{7}+\dfrac{2}{7}\right)+\dfrac{6}{11}=\dfrac{5}{11}.1+\dfrac{6}{11}=\dfrac{5}{11}+\dfrac{6}{11}=\dfrac{11}{11}=1\)

\(B=\dfrac{3}{13}.\dfrac{6}{11}+\dfrac{3}{13}.\dfrac{9}{11}-\dfrac{3}{13}.\dfrac{4}{11}=\dfrac{3}{13}\left(\dfrac{6}{11}+\dfrac{9}{11}-\dfrac{4}{11}\right)=\dfrac{3}{13}.1=\dfrac{3}{13}\)

\(C=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{1}{2}-\dfrac{1}{3}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right)\left(\dfrac{3}{6}-\dfrac{2}{6}-\dfrac{1}{6}\right)=\left(\dfrac{12}{16}-\dfrac{31}{22}+\dfrac{14}{91}\right).0=0\)

\(B=6-7-8+9-10+11+12-13+14-15-16+17-18\)

\(B=6-7-8-10-13-15-16-18+9+11+12+14+17\)

\(B=6+-7+-8+-10+-13+-15+-16+-18+9+11+12+14+17\)

\(B=\left(6+-7\right)+\left(-8+9\right)+\left(-10+11\right)+\left(-13+12\right)+\left(-15+14\right)+\left(-18+17\right)+-16\)

\(B=-1+1+1+-1+-1+-1+-16=-16+-2\)

\(B=-18\)

A = ( 879 - 2879) - ( 1876 - 1865 ) = -2000 - 11 = -2011

Bạn nhóm các cặp lại rồi chuyển vế :

\(A=879-1876+1865-2879=879-2879+1865-1876\)

\(=\left(879-2879\right)-1876+1865\)Đưa 1876 với 1865 vô ngoặc

Chuyển cộng thành trừ :

\(=\left(879-2879\right)-\left(1876-1865\right)\)

\(=-2000-11=-2011\)

a) \(\dfrac{7}{30}+\dfrac{\left(-12\right)}{37}+\dfrac{23}{30}+\dfrac{\left(-25\right)}{37}=\left(\dfrac{7}{30}+\dfrac{23}{30}\right)+\left(\dfrac{-12}{37}+\dfrac{-25}{37}\right)=1+\left(-1\right)=0\)

b) \(\dfrac{5}{7}\cdot\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}=\dfrac{5}{7}\cdot\left(\dfrac{5}{11}+\dfrac{2}{11}-\dfrac{14}{11}\right)=\dfrac{5}{7}\cdot\left(-\dfrac{7}{11}\right)=-\dfrac{5}{11}\)

c) \(\dfrac{\left(-5\right)}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}\cdot\left(-1\right)+\dfrac{12}{7}=\left(-\dfrac{5}{7}\right)+\dfrac{12}{7}=\dfrac{7}{7}=1\)

3/7 + 4/9 + 5/11 + 8/14 + 10/18 + 12/22

= 3/7 + 4/9 + 5/11 + 4/7 + 5/9 + 6/11

= ( 3/7 + 4/7 ) + ( 4/9 + 5/9 ) + ( 5/11 + 6/11 )

= 7/7 +9/9 + 11/11

= 1 + 1 + 1 

= 3 

tk mk nha , cảm ơn ạ , được ko á ?????????

3/7 + 4/9 + 5/11 + 8/14 + 10/18 + 12/22 = 3

\(\frac{3}{7}\)+ \(\frac{4}{9}\)+ \(\frac{5}{11}\)+ \(\frac{8}{14}\)+ \(\frac{10}{18}\)+ \(\frac{12}{22}\)

= \(\frac{55}{63}\)+ \(\frac{5}{11}\)+ \(\frac{8}{14}\)+ \(\frac{10}{18}\)+ \(\frac{12}{22}\)

= \(\frac{920}{693}\)+ \(\frac{8}{14}\)+ \(\frac{10}{18}\)+ \(\frac{12}{22}\)

= \(\frac{188}{99}\)+ \(\frac{10}{18}\)+ \(\frac{12}{22}\)

= \(\frac{27}{11}\)+ \(\frac{12}{22}\)

= \(3\)

các bn nào đang online giải hộ mk vs

a)\(\frac{21}{11}.\frac{22}{17}.\frac{68}{63}=\frac{21.22.68}{11.17.63}=\frac{21.2.11.4.17}{11.17.3.21}=\frac{\left(11.17.21\right)2.4}{\left(11.17.21\right).3}=\frac{2.4}{3}=\frac{8}{3}\)

b)\(\frac{5}{14}.\frac{7}{13}.\frac{26}{25}=\frac{5.7.26}{14.13.25}=\frac{5.7.13.2}{7.2.13.5.5}=\frac{\left(5.7.13\right).2}{\left(5.7.13\right).2.5}=\frac{2}{2.5}=\frac{1}{5}\)