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\(B=\frac{1}{7}\left(\frac{5}{2}+\frac{4}{11}+\frac{3}{22}+\frac{11}{30}+\frac{13}{60}\right)\)
\(B=\frac{1}{7}\left(\frac{5}{2}+\frac{11}{22}+\frac{35}{60}\right)\)
quy đồng tính nốt ra \(B=\frac{43}{84}\)
Nhớ bấm L I K E cho mk nhá :))))
B=1/7.(555/222+4444/1221+33333/244442+11/330+13/60
B= 1/7.(5/2+4/11+3/22+11/330+13/60)
B= 1/7.(1650/660+240/660+90/660+22/660+143/660)
B=1/7.143/44
B=143/308
k mk nha, k xong bình luận bên dưới mk k lại cho
1) âm năm phần 12
2) âm mười bảy phần 9
3) -1
Đây là đáp án còn làm bài từ làm nhé
bài 3:
\(A=\dfrac{9}{1\cdot2}+\dfrac{9}{2\cdot3}+\dfrac{9}{3\cdot4}+...+\dfrac{9}{2021\cdot2022}\)
\(=9\left(\dfrac{1}{1\cdot2}+\dfrac{1}{2\cdot3}+...+\dfrac{1}{2021\cdot2022}\right)\)
\(=9\left(1-\dfrac{1}{2}+\dfrac{1}{2}-\dfrac{1}{3}+...+\dfrac{1}{2021}-\dfrac{1}{2022}\right)\)
\(=9\cdot\dfrac{2021}{2022}=\dfrac{6063}{674}\)
Bài 1:
a: \(\left(\dfrac{1}{2}+\dfrac{16}{30}\right)-\left(1+\dfrac{1}{30}\right)\)
\(=\dfrac{15+16}{30}-1-\dfrac{1}{30}\)
\(=\dfrac{30}{30}-1\)
=1-1
=0
b: \(\dfrac{-5}{11}\cdot\dfrac{4}{13}+\dfrac{-5}{11}\cdot\dfrac{9}{13}+3\dfrac{5}{11}\)
\(=-\dfrac{5}{11}\left(\dfrac{4}{13}+\dfrac{9}{13}\right)+3+\dfrac{5}{11}\)
\(=-\dfrac{5}{11}+3+\dfrac{5}{11}\)
=3
c: \(3^2-12\left(\dfrac{3}{4}-\dfrac{2}{3}\right)\)
\(=9-12\cdot\dfrac{9-8}{12}\)
=9-1
=8
11: \(=\dfrac{-5}{7}+\dfrac{5}{67}+\dfrac{13}{30}+\dfrac{1}{2}-\dfrac{11}{6}+\dfrac{17}{14}+\dfrac{2}{5}\)
\(=\left(\dfrac{-5}{7}+\dfrac{1}{2}+\dfrac{17}{14}\right)+\left(\dfrac{13}{30}-\dfrac{11}{6}+\dfrac{2}{5}\right)+\dfrac{5}{67}\)
\(=\dfrac{-10+7+17}{14}+\dfrac{13-55+12}{30}+\dfrac{5}{67}\)
\(=1-1+\dfrac{5}{67}=\dfrac{5}{67}\)
12: \(=\dfrac{-1}{4}\cdot\dfrac{152}{11}-\dfrac{1}{4}\cdot\dfrac{68}{11}\)
\(=\dfrac{-1}{4}\left(\dfrac{152}{11}+\dfrac{68}{11}\right)=-\dfrac{1}{4}\cdot20=-5\)
\(A=\dfrac{1}{7}\left(\dfrac{555}{777}+\dfrac{4444}{12221}+\dfrac{33333}{244442}+\dfrac{11}{30}+\dfrac{13}{30}\right)\)
\(=\dfrac{1}{7}\left(\dfrac{5}{7}+\dfrac{4}{11}+\dfrac{3}{22}+\dfrac{23}{30}\right)\\ =\dfrac{1}{7}\left(\dfrac{5}{7}+\dfrac{1}{2}+\dfrac{23}{30}\right)\\ =\dfrac{1}{7}\cdot\dfrac{208}{105}\\ =\dfrac{208}{735}\)