\(\dfrac{-5}{7}\cdot\dfrac{3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+1\dfrac{5}{7}=\dfrac{5}{7}\cdot\dfrac{-3}{13}-\dfrac{5}{7}\cdot\dfrac{10}{13}+\dfrac{12}{7}\cdot1=\dfrac{5}{7}\cdot\left(\dfrac{-3}{13}-\dfrac{10}{13}\right)+\dfrac{12}{7}=\dfrac{5}{7}-1+\dfrac{12}{7}=-\dfrac{5}{7}+\dfrac{12}{7}=\dfrac{7}{7}=1\)

=-5/7(3/13+10/13)+12/7

=-5/7+12/7=1

\(=\dfrac{5}{7}\cdot\left(-\dfrac{3}{13}+\dfrac{10}{13}+1\right)=\dfrac{5}{7}\cdot8=\dfrac{40}{7}\)

\(A=\frac{155-\frac{10}{7}-\frac{5}{11}+\frac{5}{23}}{403-\frac{26}{7}-\frac{13}{11}+\frac{13}{23}}-\frac{\frac{3}{5}+\frac{3}{13}-0,9}{\frac{7}{91}+0,2-\frac{3}{10}}\)

\(A=\frac{155-5\left(\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}{403-13\left(\frac{2}{7}-\frac{1}{11}+\frac{1}{23}\right)}-\frac{\frac{3}{5}+\frac{3}{13}-\frac{9}{10}}{\frac{7}{91}+\frac{2}{10}-\frac{3}{10}}\)

\(A=\frac{155-5}{403-13}-\frac{3\left(\frac{1}{5}+\frac{1}{13}\right)-\frac{9}{10}}{\frac{7}{91}+\left(-\frac{1}{10}\right)}\)

\(A=\frac{5}{13}-\frac{\left(-\frac{9}{130}\right)}{\left(-\frac{3}{130}\right)}=\frac{5}{13}-\frac{\frac{9}{130}}{\frac{3}{130}}\)

\(A=\frac{5}{13}-\frac{9}{130}\cdot\frac{130}{3}\)

\(A=\frac{5}{13}-3=-\frac{34}{13}\)

\(B=\frac{30\cdot4^7\cdot3^{29}-5\cdot14^5\cdot2^{12}}{54\cdot6^{14}\cdot9^7-12\cdot8^5\cdot7^5}\)

\(B=\frac{30\cdot\left(2^2\right)^7\cdot3^{29}-5\cdot\left(2\cdot7\right)^5\cdot2^{12}}{54\cdot\left(2\cdot3\right)^{14}\cdot\left(3^2\right)^7-12\cdot\left(2^3\right)^5\cdot7^5}\)

\(B=\frac{30\cdot2^{14}\cdot3^{29}-5\cdot2^5\cdot7^5\cdot2^{12}}{54\cdot2^{14}\cdot3^{14}\cdot3^{14}-12\cdot2^{15}\cdot7^5}\)

\(B=\frac{30\cdot3^{29}-5\cdot2^{17}\cdot7^5}{54\cdot3^{28}-12\cdot2^{15}\cdot7^5}=\frac{30\cdot3-5\cdot2^2}{54-12}=\frac{5}{3}\)

1: \(A=\dfrac{5\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}{13\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}+\dfrac{3\left(\dfrac{1}{5}+\dfrac{1}{13}-\dfrac{3}{10}\right)}{\dfrac{1}{13}+\dfrac{1}{5}-\dfrac{3}{10}}\)

=5/13+3

=5/13+39/13

=44/13

2: \(B=\dfrac{2^{15}\cdot3^{30}\cdot5-5\cdot2^5\cdot7^5\cdot2^{12}}{3^3\cdot2\cdot2^{14}\cdot3^{14}\cdot3^{14}-2^2\cdot3\cdot2^{15}\cdot7^5}\)

\(=\dfrac{5\cdot2^{15}\left(3^{30}-2^2\cdot7^5\right)}{3^{31}\cdot2^{15}-2^{17}\cdot3\cdot7^5}\)

\(=\dfrac{5\cdot2^{15}\left(3^{30}-2^2\cdot7^5\right)}{3\cdot2^{15}\cdot\left(3^{30}-2^2\cdot7^5\right)}=\dfrac{5}{3}\)

a: \(A=\dfrac{5\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}{13\left(31-\dfrac{2}{7}-\dfrac{1}{11}+\dfrac{1}{23}\right)}+\dfrac{3\left(\dfrac{1}{5}+\dfrac{1}{13}-\dfrac{3}{10}\right)}{\left(\dfrac{1}{5}-\dfrac{3}{10}+\dfrac{1}{13}\right)}\)

=5/13+3

=5/13+39/13

=44/13

b: \(B=\dfrac{3^{30}\cdot2^{15}\cdot5-5\cdot2^5\cdot7^5\cdot2^{12}}{2\cdot3^3\cdot2^{14}\cdot3^{14}\cdot3^{14}-3\cdot2^2\cdot2^{15}\cdot7^5}\)

\(=\dfrac{2^{15}\cdot5\left(3^{30}-7^5\cdot2^2\right)}{2^{15}\cdot3^{31}-3\cdot2^{17}\cdot7^5}\)

\(=\dfrac{2^{15}\cdot5\left(3^{30}-7^5\cdot2^2\right)}{2^{15}\cdot3\left(3^{30}-7^5\cdot2^2\right)}=\dfrac{5}{3}\)

a)29 . (19 – 13) – 19 . (29 – 13)

= 29 . 6 – 19 . 16

= 174 – 304

= –130.

b)31.(-18)+31.(-81)-31       

= 31. [-18 + (-81) - 1 ]

= 31. (-100)

= -3100

c)(7.3-3):(-6)  

(7.3-3):(-6)

= (21-3):(-6)

= 18 : (-6)

= 3

d)72:[(-6).2+4)]       

= 72 : ( -12 + 4 )

= 72 : -8

= -9

Bài 2:

a)(-12).47+(-12).52+(-12)       

= (-12).(47+52+1)

= -1200

b)13.(23+22)-3.(17+28)  

13 . (23 + 22) - 3 . (17 + 28)

= 13 . 45 - 3 . 45

= ( 13 - 3 ) . 45

= 10 . 45

= 450

c)18-10:(-2)-7   

= 18-5+7

= 13+7

= 20

d)99:[(-7).2+5)

1. Tính nhanh

a) 29 . (19 – 13) – 19 . (29 – 13)

= 29 . 6 – 19 . 16

= 174 – 304

= –130.

b) 31 . (-18) + 31 . (-81) - 31       

= 31. [-18 + (-81) - 1 ]

= 31. (-100)

= -3100

c) (7 . 3 - 3) : (-6)

= (21 - 3) : (-6)

= 18 : (-6)

= 3

d) 72 : [(-6) . 2 + 4)]       

= 72 : ( -12 + 4 )

= 72 : -8

= -9

2. Tính nhanh

a) (-12) . 47 + (-12) . 52 + (-12)

= (-12) . (47 + 52 + 1)

= (-12) . 100

= -1200        
b) 13 . (23 + 22) - 3 . (17 + 28)   

= 13 . 45 - 3 . 45

= (13 - 3) . 45

= 10 . 45

= 450
c) 18 - 10 : (-2) - 7   

= 18-5+7

= 13+7

= 20

d) 99 : [(-7) . 2 + 5]

= 99 : -9

= -11

1) = \(\frac{3}{5}\)

2) =\(\frac{6}{7}\)

3)\(\frac{9}{13}\)

4)\(\frac{4}{13}\)

a, \(4^7.3^4.9^6:6^{13}\)

\(=\left(2^{14}.3^4.3^{12}\right):\left(2^{13}.3^{13}\right)\)

\(=2^{14}:2^{13}.3^{16}:3^{13}\)

\(=2.3^3=54\)

b, \(2^3.3^2-5^{16}:25^7\)

\(=72-5^{16}:5^{14}\)

\(=72-5^2=47\)

4^7.3^4.9^6:6^13=4^7.3^4.(3^2)^6:6^13

=4^7.3^16:3^13.2^13

=(2^2)^7.3^16:3^13.2^13

=2^14.3^16:3^13.2^13

=2.3^3

=54

khó quá mk giải miết mà không ra

khó vãi