\(\dfrac{7}{23}\)*[(\(\dfrac{8}{6}\))+\(\dfrac{45}{18}\)]
(nếu có cách nhanh càng tốt nha các bạn,THANK YOU!!!!)
>; <; = ?
a) \(\dfrac{4}{7}\) \(\dfrac{6}{7}\) \(\dfrac{15}{23}\)
\(\dfrac{12}{23}\) \(\dfrac{45}{60}\)
\(\dfrac{3}{4}\)
b) \(\dfrac{8}{9}\) \(\dfrac{11}{18}\) \(\dfrac{13}{18}\)
\(\dfrac{2}{3}\) \(\dfrac{27}{25}\)
1
a) \(\dfrac{4}{7}< \dfrac{6}{7}\)
\(\dfrac{15}{23}>\dfrac{12}{23}\)
\(\dfrac{45}{60}=\dfrac{3}{4}\)
b) \(\dfrac{8}{9}>\dfrac{11}{18}\)
\(\dfrac{13}{18}>\dfrac{2}{3}\)
\(\dfrac{27}{25}>1\)
1, 12:(\(\dfrac{3}{4}\)-\(\dfrac{5}{6}\))2
2,\(\dfrac{7}{23}\).[(-\(\dfrac{8}{6}\))-\(\dfrac{45}{18}\)]
mik cần gấp nên bn nào giúp mik với ạk
1, \(12:\left(\dfrac{3}{4}-\dfrac{5}{6}\right)^2=12:\left(-\dfrac{1}{12}\right)^2=12:\dfrac{1}{144}=1728\)
2, \(\dfrac{7}{23}.\left(-\dfrac{8}{6}-\dfrac{45}{18}\right)=\dfrac{7}{23}.-\dfrac{23}{6}=-\dfrac{7}{6}\)
1) 12 : (3/4 - 5/6)2
= 12 : (-1/12)2
= 12 : 1/144
=1728
2) 7/23 . (-8/6 - 45/18)
= 7/23 . (-23/6)
= -7/6
Chúc bạn học tốt!! ^^
3) \(\dfrac{7}{23}.\left[\left(-\dfrac{8}{6}\right)-\dfrac{45}{18}\right]\)
\(\dfrac{7}{23}\cdot\left[\dfrac{-8}{6}-\dfrac{15}{48}\right]\)
\(=\dfrac{7}{23}\cdot\dfrac{-64-15}{48}\)
\(=\dfrac{7}{23}\cdot\dfrac{-69}{48}\)
\(=-3\cdot\dfrac{7}{48}=\dfrac{-7}{16}\)
BT2: Tính nhanh
7) \(-1\dfrac{5}{7}.15+\dfrac{2}{7}.\left(-15\right)+\left(-105\right).\left(\dfrac{2}{3}-\dfrac{4}{5}+\dfrac{1}{7}\right)\)
8) \(\dfrac{13}{29}\left(\dfrac{29}{5}-\dfrac{45}{8}\right)-\dfrac{45}{8}\left(\dfrac{9}{8}-\dfrac{13}{29}\right)\)
Các bạn giúp mk nhé! Thank!
7: \(=\dfrac{-12}{7}\cdot15+\dfrac{2}{7}\cdot\left(-15\right)+\left(-105\right)\cdot\dfrac{70-84+15}{105}\)
\(=\dfrac{-12\cdot15+2\cdot\left(-15\right)}{7}-1\)
\(=\dfrac{-15\cdot14}{7}-1=-15\cdot2-1=-31\)
8: \(=\dfrac{13}{29}\cdot\dfrac{29}{5}-\dfrac{13}{29}\cdot\dfrac{45}{8}-\dfrac{45}{8}\cdot\dfrac{9}{8}+\dfrac{45}{8}\cdot\dfrac{13}{29}\)
\(=-\dfrac{1193}{320}\)
Tính nhanh (nếu có thể):
a) \(5\dfrac{5}{27}+\dfrac{7}{23}+0,5.\dfrac{5}{27}+\dfrac{16}{23}\)
b) \(\dfrac{10^9.49^4}{14^8.25^5}\)
các bn ghi rõ cách giải giùm mình đcc ko, mình cảm ơn
a) https://hoc247.net/hoi-dap/toan-7/thuc-hien-phep-tinh-5-5-27-7-23-0-5-5-27-16-23-faq218258.html
b) https://hoidap247.com/cau-hoi/1507941
b) \(\dfrac{10^9.49^4}{14^8.25^5}=\dfrac{\left(2.5\right)^9.\left(7^2\right)^4}{\left(7.2\right)^8.\left(5^2\right)^5}=\dfrac{2^9.5^9.7^6}{7^8.2^8.5^{10}}=\dfrac{2}{7.7.5}=\dfrac{2}{245}\)
\(a,=\left(\dfrac{140}{27}+\dfrac{1}{2}\cdot\dfrac{5}{27}\right)+\left(\dfrac{7}{23}+\dfrac{16}{23}\right)\\ =\left(\dfrac{140}{27}+\dfrac{5}{54}\right)+1=\dfrac{285}{54}+1=\dfrac{339}{54}=\dfrac{113}{18}\\ b,=\dfrac{2^9\cdot5^9\cdot7^8}{7^8\cdot2^8\cdot5^{10}}=\dfrac{2}{5}\)
Bạn Hoàng làm phép nhân \(4\dfrac{3}{7}.2\) như sau :
\(4\dfrac{3}{7}.2=\dfrac{31}{7}.2=\dfrac{31}{7}.\dfrac{2}{1}=8\dfrac{6}{7}\)
Có cách nào tính nhanh hơn không ? Nếu có, hãy giải thích cách làm đó ?
a) Bạn Cường đã viết hỗn số dưới dạng phân số rồi cộng
b) Cách khác để tính nhanh hơn như sau:
Bài 3: Tính hợp lí các giá trị biểu thức sau
A= \(49\dfrac{8}{23}=-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)\)
B=\(71\dfrac{38}{45}-\left(43\dfrac{8}{45}-1\dfrac{17}{57}\right)\)
a: \(A=49+\dfrac{8}{23}-14-\dfrac{8}{23}-5-\dfrac{7}{32}=30-\dfrac{7}{32}=\dfrac{953}{32}\)
b:
Sửa đề: \(B=71\dfrac{38}{45}-\left(43\dfrac{8}{45}-1\dfrac{17}{51}\right)\)
\(B=71+\dfrac{38}{45}-43-\dfrac{8}{45}+1+\dfrac{17}{51}\)
\(=71-43+1+1\)
=28+2=30
Bài 3: Tính hợp lí các giá trị biểu thức sau:
A=\(49\dfrac{8}{23}-\left(5\dfrac{7}{32}+14\dfrac{8}{23}\right)\)
B=\(71\dfrac{38}{45}-\left(43\dfrac{8}{45}-1\dfrac{17}{57}\right)\)
a: \(A=49+\dfrac{8}{23}-14-\dfrac{8}{23}-5-\dfrac{7}{32}=30-\dfrac{7}{32}=\dfrac{953}{32}\)
b:
Sửa đề: \(B=71\dfrac{38}{45}-\left(43\dfrac{8}{45}-1\dfrac{17}{51}\right)\)
\(B=71+\dfrac{38}{45}-43-\dfrac{8}{45}+1+\dfrac{17}{51}\)
\(=71-43+1+1\)
=28+2=30
ĐỀ 1:
1. Tính:
a. \(\dfrac{7}{23}\left[\left(\dfrac{-8}{6}\right)-\dfrac{45}{18}\right]\)
b. \(\dfrac{1}{5}:\dfrac{1}{10}-\dfrac{1}{3}\left(\dfrac{6}{5}-\dfrac{9}{4}\right)\)
c. \(\dfrac{3}{5}.\left(\dfrac{-8}{3}\right)-\dfrac{3}{5}:\left(-6\right)\)
d. \(\dfrac{1}{2}\left(\dfrac{4}{3}+\dfrac{2}{5}\right)-\dfrac{3}{4}\left(\dfrac{8}{9}+\dfrac{16}{3}\right)\)
e. \(\dfrac{6}{7}:\left(\dfrac{3}{26}-\dfrac{3}{13}\right)+\dfrac{6}{7}\left(\dfrac{1}{10}-\dfrac{8}{5}\right)\)
2. Tìm x, biết:
a. \(1\dfrac{2}{5}x+\dfrac{3}{7}=\dfrac{4}{5}\)
b. |x - 1,5| = 2
c. \(\dfrac{4}{5}-\left|x-\dfrac{1}{6}\right|=\dfrac{2}{3}\)
d. 3x . 2x = 216
e. \(\dfrac{1}{2}\left(x-\dfrac{1}{3}\right)+\dfrac{-1}{2}=\dfrac{3}{4}\)
* Lm nhanh nha
Ths you <3
1.Tính
a.\(\dfrac{7}{23}\left[(-\dfrac{8}{6})-\dfrac{45}{18}\right]=\dfrac{7}{23}.-\dfrac{12}{6}=-\dfrac{7}{6}\)
b.\(\dfrac{1}{5}\div\dfrac{1}{10}-\dfrac{1}{3}(\dfrac{6}{5}-\dfrac{9}{4})=2-(-\dfrac{7}{20})=\dfrac{47}{20}\)
c.\(\dfrac{3}{5}.(-\dfrac{8}{3})-\dfrac{3}{5}\div(-6)=-\dfrac{3}{2}\)
d.\(\dfrac{1}{2}.(\dfrac{4}{3}+\dfrac{2}{5})-\dfrac{3}{4}.(\dfrac{8}{9}+\dfrac{16}{3})=-\dfrac{19}{5}\)
e.\(\dfrac{6}{7}\div(\dfrac{3}{26}-\dfrac{3}{13})+\dfrac{6}{7}.(\dfrac{1}{10}-\dfrac{8}{5})=-\dfrac{61}{7}\)
Bài 2
a.\(1^2_5x+\dfrac{3}{7}=\dfrac{4}{5}\)
\(x=\dfrac{13}{49}\)
b.\(\left|x-1,5\right|=2\)
Xảy ra 2 trường hợp
TH1
\(x-1,5=2\)
\(x=3,5\)
TH2
\(x-1,5=-2\)
\(x=-0,5\)
Vậy \(x=3,5\) hoặc \(x=-0,5\) .
Ngại làm quá trời ơi,lần sau bn tách ra nhá làm vậy mỏi tay quá.