\(\dfrac{2}{3}+\dfrac{1}{3}.\left(-\dfrac{4}{9}+\dfrac{5}{6}\ri...">
K
Khách

Hãy nhập câu hỏi của bạn vào đây, nếu là tài khoản VIP, bạn sẽ được ưu tiên trả lời.

6 tháng 7 2021

\(=\dfrac{2}{3}+\dfrac{1}{3}.\dfrac{7}{18}.\dfrac{12}{7}\)

\(=\dfrac{2}{3}+\dfrac{7.3.2.2}{3.7.3.2.3}\)

\(=\dfrac{2}{3}+\dfrac{2}{9}=\dfrac{8}{9}\)

6 tháng 7 2021

TICK CHO MÌNH NHÉ

Giải:

\(\dfrac{2}{3}\) + \(\dfrac{1}{3}\) . (\(-\dfrac{4}{9}\) + \(\dfrac{5}{6}\) ) : \(\dfrac{7}{12}\)

 = \(\dfrac{2}{3}\)  + \(^{\dfrac{1}{3}}\) . \(\dfrac{7}{18}\) : \(\dfrac{7}{12}\)

 = \(\dfrac{2}{3}\) + \(\dfrac{7}{54}\) : \(\dfrac{7}{12}\)

 = \(\dfrac{2}{3}\) + \(\dfrac{2}{9}\)

 = \(\dfrac{8}{9}\)

17 tháng 4 2017

\(A=11\dfrac{3}{13}-\left(2\dfrac{4}{7}+5\dfrac{3}{13}\right)\)

\(A=11\dfrac{3}{13}-5\dfrac{3}{13}-2\dfrac{4}{7}\)

\(A=6-2\dfrac{4}{7}\)

\(A=5\dfrac{7}{7}-2\dfrac{4}{7}\)

\(A=3\dfrac{3}{7}\)

\(B=\left(6\dfrac{4}{9}+3\dfrac{7}{11}\right)-4\dfrac{4}{9}\)

\(B=\left(6\dfrac{4}{9}-4\dfrac{4}{9}\right)+3\dfrac{7}{11}\)

\(B=2+3\dfrac{7}{11}\)

\(B=5\dfrac{7}{11}\)

\(C=\dfrac{-5}{7}.\dfrac{2}{11}+\dfrac{-5}{7}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\left(\dfrac{2}{11}+1\right)-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-5}{7}.\dfrac{13}{11}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{-65}{77}-\dfrac{9}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{4}{11}+1\dfrac{5}{7}\)

\(C=\dfrac{160}{11}\)

\(D=0,7.2\dfrac{2}{3}.20.0,375.\dfrac{5}{28}\)

\(D=\dfrac{7}{10}.\dfrac{8}{3}.20.\dfrac{375}{1000}.\dfrac{5}{28}\)

\(D=\dfrac{7}{28}=\dfrac{5}{2}\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-0,25-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{3}-\dfrac{1}{4}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right)\left(\dfrac{1}{12}-\dfrac{1}{12}\right)\)

\(E=\left(-6,17+3\dfrac{5}{9}-2\dfrac{36}{97}\right).0\)

\(\Rightarrow E=0\)

17 tháng 4 2017

19 tháng 4 2017

Gợi ý: Sử dụng tính chất phân phối của phép nhân đối với phép cộng để nhóm thừa số chung ra ngoài.

Giải bài 76 trang 39 SGK Toán 6 Tập 2 | Giải toán lớp 6

17 tháng 4 2017

ính giá trị của các biểu thức sau:

A=827−(349+427)A=827−(349+427)

B=(1029+235)−629B=(1029+235)−629

Giải:

A=827−(349+427)A=827−(349+427)

=587−(319+307)=58−307−319=4−319=587−(319+307)=58−307−319=4−319

= 36−319=5936−319=59

B=(1029+235)−629B=(1029+235)−629

=1029−629+235=4+235=635

17 tháng 4 2017

ính giá trị của các biểu thức sau:

A
=
8
2
7

(
3
4
9
+
4
2
7
)
A=827−(349+427)

B
=
(
10
2
9
+
2
3
5
)

6
2
9
B=(1029+235)−629

Giải:

A
=
8
2
7

(
3
4
9
+
4
2
7
)
A=827−(349+427)


=
58
7

(
31
9
+
30
7
)
=
58

30
7

31
9
=
4

31
9
=587−(319+307)=58−307−319=4−319

=
36

31
9
=
5
9
36−319=59

B
=
(
10
2
9
+
2
3
5
)

6
2
9
B=(1029+235)−629


=
10
2
9

6
2
9
+
2
3
5
=
4
+
2
3
5
=
6
3
5

Xem thêm tại: http://loigiaihay.com/bai-100-trang-47-sgk-toan-6-tap-2-c41a24737.html#ixzz4eUGN0ooE

a: \(=\dfrac{5\cdot\left(8-6\right)}{10}=\dfrac{5\cdot2}{10}=1\)

b: \(\dfrac{\left(-4\right)^2}{5}=\dfrac{16}{5}\)

\(B=\dfrac{3}{7}-\dfrac{1}{5}-\dfrac{3}{7}=-\dfrac{1}{5}\)

c: \(C=\left(6-2.8\right)\cdot\dfrac{25}{8}-\dfrac{8}{5}\cdot4\)

\(=\dfrac{16}{5}\cdot\dfrac{25}{8}-\dfrac{32}{5}\)

\(=5\cdot2-\dfrac{32}{5}=10-\dfrac{32}{5}=\dfrac{18}{5}\)

d: \(D=\left(\dfrac{-5}{24}+\dfrac{18}{24}+\dfrac{14}{24}\right):\dfrac{-17}{8}\)

\(=\dfrac{27}{24}\cdot\dfrac{-8}{17}=\dfrac{-9}{8}\cdot\dfrac{8}{17}=\dfrac{-9}{17}\)

a: \(=\dfrac{157}{8}\cdot\dfrac{12}{7}-\dfrac{61}{4}\cdot\dfrac{12}{7}\)

\(=\dfrac{12}{7}\left(\dfrac{157}{8}-\dfrac{122}{8}\right)\)

\(=\dfrac{12}{7}\cdot\dfrac{35}{8}=5\cdot\dfrac{3}{2}=\dfrac{15}{2}\)

b: \(=\dfrac{2}{15}-\dfrac{2}{15}\cdot5+\dfrac{3}{15}\)

\(=\dfrac{1}{3}-\dfrac{2}{3}=-\dfrac{1}{3}\)

c: \(=\left(\dfrac{10}{3}+\dfrac{5}{2}\right):\left(\dfrac{19}{6}-\dfrac{21}{5}\right)-\dfrac{11}{31}\)

\(=\dfrac{35}{6}:\dfrac{-31}{30}-\dfrac{11}{31}\)

\(=\dfrac{35}{6}\cdot\dfrac{30}{-31}-\dfrac{11}{31}\)

\(=\dfrac{-35\cdot5-11}{31}=\dfrac{-186}{31}=-6\)

3 tháng 7 2018

G=\(\dfrac{\left(-2\right)}{3}+\dfrac{\left(-5\right)}{7}+\dfrac{2}{3}+\dfrac{\left(-2\right)}{7}\)

\(\Rightarrow G=\dfrac{\left(-2\right)}{3}+\dfrac{2}{3}+\dfrac{\left(-5\right)}{7}+\dfrac{\left(-2\right)}{7}\)

\(\Rightarrow G=\dfrac{\left(-2\right)+2}{3}+\dfrac{\left(-5\right)+\left(-2\right)}{7}\)

\(\Rightarrow G=0+\dfrac{-7}{7}\)

\(\Rightarrow G=-1\)

\(H=\dfrac{\left(-5\right)}{7}\cdot\dfrac{2}{11}+\dfrac{\left(-5\right)}{7}\cdot\dfrac{9}{11}\)

\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot\left(\dfrac{2}{11}+\dfrac{9}{11}\right)\)\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot\left(\dfrac{2+9}{11}\right)\)

\(\Rightarrow H=\dfrac{\left(-5\right)}{7}\cdot1\)

\(\Rightarrow H=\dfrac{-5}{7}\)

11 tháng 8 2017

3) \(\dfrac{5}{3}.\dfrac{11}{2}+\dfrac{1}{4}\)

\(=\dfrac{5.11}{3.2}+\dfrac{1}{4}\)\

\(=\dfrac{55}{6}+\dfrac{1}{4}\)

\(=\dfrac{220}{24}+\dfrac{6}{24}\)

\(=\dfrac{226}{24}\)

\(=\dfrac{113}{12}\)

4) \(\left(\dfrac{5}{2}-\dfrac{1}{3}\right).\dfrac{9}{2}-\dfrac{6}{7}\)

\(=\left(\dfrac{15}{6}-\dfrac{2}{6}\right).\dfrac{9}{2}-\dfrac{6}{7}\)

\(=\dfrac{13}{6}.\dfrac{9}{2}-\dfrac{6}{7}\)

\(=\dfrac{13.9}{6.2}-\dfrac{6}{7}\)

\(=\dfrac{117}{12}-\dfrac{6}{7}\)

\(=\dfrac{39}{4}-\dfrac{6}{7}\)

\(=\dfrac{273}{28}-\dfrac{24}{28}\)

\(=\dfrac{249}{28}\)

Câu 1 : Thực hiện phép tính 1 cách hợp lý : a) \(\dfrac{-12}{7}.\dfrac{4}{35}+\dfrac{12}{7}.\dfrac{\left(-31\right)}{35}-\dfrac{2}{7}\) b) \(1+2-3-4+5+5-7-8+...+97+98-99-100\) c) \(A=157.\left(-37\right)-\left(41.53-37.157\right)+51.53\) d) \(B=\left(\dfrac{1}{11}+\dfrac{1}{21}+\dfrac{1}{31}+\dfrac{1}{41}+\dfrac{1}{51}\right)\left(\dfrac{-41}{123}+\dfrac{31}{-186}-\dfrac{-51}{102}\right)\) Câu 2 : a) 12 ( x - 5 ) = 7x - 5 b) Tìm x \(\in\) Z sao cho : ( 2x - 3 ) 2010 = ( 2x...
Đọc tiếp

Câu 1 : Thực hiện phép tính 1 cách hợp lý :

a) \(\dfrac{-12}{7}.\dfrac{4}{35}+\dfrac{12}{7}.\dfrac{\left(-31\right)}{35}-\dfrac{2}{7}\)

b) \(1+2-3-4+5+5-7-8+...+97+98-99-100\)

c) \(A=157.\left(-37\right)-\left(41.53-37.157\right)+51.53\)

d) \(B=\left(\dfrac{1}{11}+\dfrac{1}{21}+\dfrac{1}{31}+\dfrac{1}{41}+\dfrac{1}{51}\right)\left(\dfrac{-41}{123}+\dfrac{31}{-186}-\dfrac{-51}{102}\right)\)

Câu 2 :

a) 12 ( x - 5 ) = 7x - 5

b) Tìm x \(\in\) Z sao cho : ( 2x - 3 ) 2010 = ( 2x - 3 ) 2012

Câu 3 :

1) Cho biểu thức S = 1 + 3 + 32 + 33 +...+ 3202 + 3 203

a) chứng tỏ rằng tổng S chia hết cho 52 .

b) Tìm Chữ số tận cùng trong tổng S .

2 ) Cho biểu thức A= \(\dfrac{2n+1}{2n+5}\) . Chứng tỏ rằng với mọi số tự nhiên n thì A là phân số tối giản .

Câu 4 : So sánh tổng gồm 1006 số hạng :

\(S=\dfrac{1}{1.1.3}+\dfrac{1}{2.3.5}+\dfrac{1}{3.5.7}+...+\dfrac{1}{1006.2011.2013}\) với \(\dfrac{2}{3}\)

1
10 tháng 12 2022

Câu 2:

a: \(\Leftrightarrow12x-60=7x-5\)

=>5x=55

=>x=11

b: \(\Leftrightarrow\left(2x-3\right)^{2010}\left[\left(2x-3\right)^2-1\right]=0\)

=>(2x-3)(2x-2)(2x-4)=0

hay \(x\in\left\{\dfrac{3}{2};1;2\right\}\)

Tính giá trị biểu thức : 1. \(A=\dfrac{\dfrac{2}{5}+\dfrac{2}{7}-\dfrac{2}{9}-\dfrac{2}{11}}{\dfrac{4}{5}+\dfrac{4}{7}-\dfrac{4}{9}-\dfrac{4}{11}}\) 2. \(B=\dfrac{1^2}{1\cdot2}\cdot\dfrac{2^2}{2\cdot3}\cdot\dfrac{3^2}{3\cdot4}\cdot\dfrac{4^2}{4\cdot5}\) 3. \(C=\dfrac{2^2}{1\cdot3}\cdot\dfrac{3^2}{2\cdot4}\cdot\dfrac{4^2}{3\cdot5}\cdot\dfrac{5^2}{4\cdot6}\cdot\dfrac{5^2}{4\cdot6}\) 4. \(D=\left(\dfrac{4}{5}-\dfrac{1}{6}\right)\cdot\left(\dfrac{2}{3}\cdot\dfrac{1}{4}\right)^2\) 5....
Đọc tiếp

Tính giá trị biểu thức :

1. \(A=\dfrac{\dfrac{2}{5}+\dfrac{2}{7}-\dfrac{2}{9}-\dfrac{2}{11}}{\dfrac{4}{5}+\dfrac{4}{7}-\dfrac{4}{9}-\dfrac{4}{11}}\)

2. \(B=\dfrac{1^2}{1\cdot2}\cdot\dfrac{2^2}{2\cdot3}\cdot\dfrac{3^2}{3\cdot4}\cdot\dfrac{4^2}{4\cdot5}\)

3. \(C=\dfrac{2^2}{1\cdot3}\cdot\dfrac{3^2}{2\cdot4}\cdot\dfrac{4^2}{3\cdot5}\cdot\dfrac{5^2}{4\cdot6}\cdot\dfrac{5^2}{4\cdot6}\)

4. \(D=\left(\dfrac{4}{5}-\dfrac{1}{6}\right)\cdot\left(\dfrac{2}{3}\cdot\dfrac{1}{4}\right)^2\)

5. Cho \(M=8\dfrac{2}{7}-\left(3\dfrac{4}{9}+4\dfrac{2}{7}\right)\) ; \(N=\left(10\dfrac{2}{9}+2\dfrac{3}{5}\right)-6\dfrac{2}{9}\). Tính \(P=M-N\)

6. \(E=10101\left(\dfrac{5}{111111}+\dfrac{5}{222222}-\dfrac{4}{3\cdot7\cdot11\cdot13\cdot37}\right)\)

7. \(F=\dfrac{\dfrac{1}{3}+\dfrac{1}{7}-\dfrac{1}{13}}{\dfrac{2}{3}+\dfrac{2}{7}-\dfrac{2}{13}}\cdot\dfrac{\dfrac{3}{4}-\dfrac{3}{16}-\dfrac{3}{256}+\dfrac{3}{64}}{1-\dfrac{1}{4}+\dfrac{1}{16}-\dfrac{1}{64}}+\dfrac{5}{8}\)

8. \(G=\text{[}\dfrac{\left(6-4\dfrac{1}{2}\right):0,03}{\left(3\dfrac{1}{20}-2,65\right)\cdot4+\dfrac{2}{5}}-\dfrac{\left(0,3-\dfrac{3}{20}\right)\cdot1\dfrac{1}{2}}{\left(1,88+2\dfrac{3}{25}\right)\cdot\dfrac{1}{80}}\text{]}:\dfrac{49}{60}\)

9. \(H=\dfrac{1}{1\cdot2\cdot3}+\dfrac{1}{2\cdot3\cdot4}+\dfrac{1}{4\cdot5\cdot6}+...+\dfrac{1}{98\cdot99\cdot100}\)

10. \(I=\dfrac{8}{9}\cdot\dfrac{15}{16}\cdot\dfrac{24}{25}\cdot...\cdot\dfrac{2499}{2500}\)

11. \(K=\left(-1\dfrac{1}{2}\right)\left(-1\dfrac{1}{3}\right)\left(-1\dfrac{1}{4}\right)...\left(-1\dfrac{1}{999}\right)\)

12. \(L=1\dfrac{1}{3}+1\dfrac{1}{8}+1\dfrac{1}{15}...\) (98 thừa số)

13. \(M=-2+\dfrac{1}{-2+\dfrac{1}{-2+\dfrac{1}{-2+\dfrac{1}{3}}}}\)

14. \(N=\dfrac{155-\dfrac{10}{7}-\dfrac{5}{11}+\dfrac{5}{23}}{403-\dfrac{26}{7}-\dfrac{13}{11}+\dfrac{13}{23}}\)

15. \(P=\left(\dfrac{1}{4}-1\right)\left(\dfrac{1}{5}-1\right)...\left(\dfrac{1}{2001}-1\right)\)

16. \(Q=\left(\dfrac{1}{1\cdot2}+\dfrac{1}{3\cdot4}+\dfrac{1}{4\cdot5}+...+\dfrac{1}{2005\cdot2006}\right):\left(\dfrac{1}{1004\cdot2006}+\dfrac{1}{1005\cdot2005}+...+\dfrac{1}{2006\cdot1004}\right)\)

2
27 tháng 11 2017

1. \(A=\dfrac{2\left(\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{9}-\dfrac{1}{11}\right)}{4\left(\dfrac{1}{5}+\dfrac{1}{7}-\dfrac{1}{9}-\dfrac{1}{11}\right)}=\dfrac{2}{4}=\dfrac{1}{2}\)

2. \(B=\dfrac{1^2.2^2.3^2.4^2}{1.2^2.3^2.4^2.5}=\dfrac{1}{5}\)

3.\(C=\dfrac{2^2.3^2.\text{4^2.5^2}.5^2}{1.2^2.3^2.4^2.5.6^2}=\dfrac{125}{36}\)

4.D=\(D=\left(\dfrac{4}{5}-\dfrac{1}{6}\right).\dfrac{4}{9}.\dfrac{1}{16}=\dfrac{19}{30}.\dfrac{1}{36}=\dfrac{19}{1080}\)

29 tháng 4 2022

hôi lì sít