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a) \(\left(6\dfrac{1}{9}+3\dfrac{7}{11}\right)-1\dfrac{1}{9}\)
\(=\left(\left(6+3\right)+\left(\dfrac{1}{9}+\dfrac{7}{11}\right)\right)-\dfrac{10}{9}\)
\(=\left(9+\dfrac{74}{99}\right)-\dfrac{10}{9}\)
\(=9\dfrac{74}{99}-\dfrac{10}{9}\)
\(=\dfrac{965}{99}-\dfrac{10}{9}\)
\(=\dfrac{95}{11}\)
b) \(1\dfrac{1}{3}-2\dfrac{5}{6}-\dfrac{6}{11}+3:5\%\)
\(=1\dfrac{1}{3}-2\dfrac{5}{6}-\dfrac{6}{11}+3:\dfrac{1}{20}\)
\(=\dfrac{4}{3}-\dfrac{17}{6}-\dfrac{6}{11}+3\cdot20\)
\(=\dfrac{4}{3}-\dfrac{17}{6}-\dfrac{6}{11}+60\)
\(=\dfrac{1275}{22}\)
c) \(4\dfrac{3}{4}-0,37+\dfrac{1}{8}-1,28-2,5+3\cdot\dfrac{1}{2}\)
\(=\dfrac{19}{4}-\dfrac{37}{100}+\dfrac{1}{8}-\dfrac{32}{25}-\dfrac{5}{2}+\dfrac{3}{2}\)
\(=\dfrac{89}{40}\)
d) \(\dfrac{5}{11}+\dfrac{5}{7}\cdot\dfrac{2}{11}-\dfrac{5}{7}\cdot\dfrac{14}{11}\)
\(=\dfrac{5}{11}+\dfrac{10}{77}-5\cdot\dfrac{2}{11}\)
\(=\dfrac{5}{11}+\dfrac{10}{77}-\dfrac{10}{11}\)
\(=-\dfrac{25}{77}\)
e) \(\dfrac{\left(2^3\cdot5\cdot7\right)\cdot\left(5^2\cdot7^3\right)}{\left(2\cdot5\cdot7^2\right)^2}\)
(câu này chờ mình một chút)
Câu e) anh rút thừa số chung là 2 cùng mũ số ra ngoài thì phân số thành số nguyên. Em nghĩ thế!
Bài 1 :
a) 0,5x - \(\dfrac{2}{3}x=\dfrac{7}{12}\)
\(\dfrac{1}{2}x-\dfrac{2}{3}x=\dfrac{7}{12}\)
\(x.\left(\dfrac{1}{2}-\dfrac{2}{3}\right)\)= \(\dfrac{7}{12}\)
\(x.\dfrac{-1}{6}=\dfrac{7}{12}\)
\(x=\dfrac{7}{12}:\dfrac{-1}{6}\)
x = \(\dfrac{-7}{2}\).
b) \(x:4\dfrac{1}{3}=-2,5\)
\(x:\dfrac{13}{3}=\dfrac{-5}{2}\)
\(x=\dfrac{-5}{2}.\dfrac{13}{3}\)
\(x=\dfrac{-15}{26}\).
c) \(\left(\dfrac{3x}{7}+1\right):\left(-4\right)=\dfrac{-1}{28}\)
\(\dfrac{3x}{7}+1=\dfrac{-1}{28}.\left(-4\right)\)
\(\dfrac{3x}{7}+1=\dfrac{1}{7}\)
\(\dfrac{3x}{7}=\dfrac{1}{7}-1\)
\(\dfrac{3x}{7}=\dfrac{-6}{7}\)
=> 3x = -6
x = -6 :3 = -2.
Bài 2 : Bài giải :
Đổi \(26\dfrac{1}{4}\)km/h = 26,25 km/h .
Độ dài quãng đường AB là :
26,25 . 2,4 = 63 (km)
Thời gian người ấy đi từ B đến A là :
63 : 30 = 2,1 ( giờ) = 2 giờ 6 phút .
Bài 3 :
\(4\dfrac{3}{4}+\left(-0,37\right)+\dfrac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\dfrac{1}{12}\)
= \(\dfrac{19}{4}+\dfrac{-37}{100}+\dfrac{1}{8}+\dfrac{-32}{25}+\dfrac{-5}{2}+\dfrac{37}{12}\)
= \(\left(\dfrac{19}{4}+\dfrac{1}{8}+\dfrac{-5}{2}\right)+\left(\dfrac{-37}{100}+\dfrac{-32}{25}\right)+\dfrac{37}{12}\)
= \(\dfrac{19}{8}+\dfrac{-33}{20}+\dfrac{37}{12}\)
= \(\dfrac{457}{120}\)
= \(3\dfrac{97}{120}\).
bn ơi, mk thấy hình như kết quả câu b bài 1 của bn sai hay sao ấy
=19/4-37/100+1/8-32/25-5/2+37/12
=(38/8+1/8-20/8)-(37/100+128/100)+37/12
=19/8-155/100+37/12
=469/120
Bài 4: 26 \(\dfrac{1}{4}\)= 26, 25 . Quãng đương là 26,25 . 2,4 = 63 km.
Thời gian đi từ B đến A là : 63 : 30 = 2,1 h
\(\left(4\frac{3}{4}+\frac{1}{8}+3\frac{1}{12}\right)-\left(0,37+1,28+2,25\right)\)
\(=7\frac{23}{24}-4,15\)
\(=7\frac{23}{24}-4\frac{3}{20}\)
\(=3\frac{97}{120}\)
\(4\dfrac{3}{4}+\left(-0,37\right)+\dfrac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\dfrac{1}{12}\)
\(=\dfrac{19}{4}+-\dfrac{37}{100}+\dfrac{1}{8}+-\dfrac{32}{25}+-\dfrac{5}{2}+\dfrac{37}{12}\)
\(=\dfrac{219}{50}+\dfrac{1}{8}+-\dfrac{32}{25}+-\dfrac{5}{2}+\dfrac{37}{12}\)
\(=\dfrac{901}{200}+-\dfrac{32}{25}+-\dfrac{5}{2}+\dfrac{37}{12}\)
\(=\dfrac{129}{40}+-\dfrac{5}{2}+\dfrac{37}{12}\)
\(=\dfrac{29}{40}+\dfrac{37}{12}\)
\(=\dfrac{457}{120}\)
Nhớ ủng hộ 1 Đúng !
\(4\dfrac{3}{4}+\left(-0,37\right)+\dfrac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\dfrac{1}{12}\)
\(=\left(4\dfrac{3}{4}+\dfrac{1}{8}+3\dfrac{1}{12}\right)+\left[\left(-0,37\right)+\left(-1,28\right)+\left(-2,5\right)\right]\)
\(=\left(\dfrac{19}{4}+\dfrac{1}{8}+\dfrac{37}{12}\right)+\left(-4,15\right)\)
\(=\dfrac{191}{24}-4,15\)
\(=\dfrac{457}{120}=3\dfrac{97}{120}\)
\(4\dfrac{3}{4}+\left(-0,37\right)+\dfrac{1}{8}+\left(-1,28\right)+\left(-2,5\right)+3\dfrac{1}{12}\)
\(=\dfrac{19}{4}+\left(-\dfrac{37}{100}\right)+\dfrac{1}{8}+\left(-\dfrac{32}{25}\right)+\left(-\dfrac{5}{2}\right)+\dfrac{37}{12}\)
=\(\dfrac{475}{100}+\left(-\dfrac{37}{100}\right)+\dfrac{1}{8}+\left(-\dfrac{32}{25}\right)+\left(-\dfrac{5}{2}\right)+\dfrac{37}{12}\)
=\(\dfrac{219}{50}+\dfrac{25}{200}+\left(-\dfrac{256}{200}\right)+\left(-\dfrac{5}{2}\right)+\dfrac{37}{12}\)
=\(\dfrac{219}{50}+\left(-\dfrac{231}{200}\right)+\left(-\dfrac{30}{12}+\dfrac{37}{12}\right)\)
=
=\(\dfrac{219}{50}+\left(-\dfrac{231}{200}\right)+\left(-\dfrac{30}{12}+\dfrac{37}{12}\right)\)
=\(\dfrac{219}{50}+\left(-\dfrac{231}{200}\right)+\dfrac{7}{12}\)
=\(\left(\dfrac{876}{200}+\left(-\dfrac{231}{200}\right)\right)+\dfrac{7}{12}\)
=\(\dfrac{129}{40}+\dfrac{7}{12}\)
=\(\dfrac{457}{120}\)
xin lỗi nha vì phần trên lúc nãy mk ấn nhầm vào gửi câu trả lời mà chưa viết xong giờ mk bổ sung thêm rồi chúng bạn có câu trả lời đúng nha