a, 6/11 : 18/11 

= 6/11 . 11/18

= 6/18 = 1/3 (gạch chéo số 11)

b,35/12 : 7/24

= 35/12 . 24/7 

=10

c,7/11 : -1/22

= 7/11 . 22/-1

= -14

d 17/5 : 34

=17/5 . 1/34

=5/2

e -25/9 : -100

= -25/9 . 1/-100

= -9/4

f -24 : -6/11

= 24. -11/6

= -44

g 5/12 chia -20

= 5/12 . 1/20

= 1/48

h 48 : 16/7

= 48 . 7/16 

= 21

nhớ t i ck nhé ( toàn gạch chéo , dễ mà )

a/ = -5/9

b/ = 13

c/= 4/3

d/ =5/9

tích đi...^.^!!!

nhìu thế 

đăng từng câu một mới có cơ có người trả lời đó bạn 

a) Ta có A = -|x| + 2

= 2 - |x|

Lại có \(\left|x\right|\ge0\forall x\Rightarrow2-\left|x\right|\le2\forall x\)

Dấu "=" xảy ra khi x = 0 

Vậy Max A = 2 <=> x = 0

b) Ta có B = -x² + 5 = 5 - x²

Lại có \(x^2\ge0\forall x\Rightarrow5-x^2\le5\forall x\)

Dấu "=" xảy  ra khi x² = 0

=> x = 0

Vậy Max B = 5 <=> x = 0

c) Ta có : C = -|x + 1| + 12 = 12 - |x + 1| 

Lại có \(\left|x+1\right|\ge0\forall x\Rightarrow12-\left|x+1\right|\le12\forall x\)

Dấu "=" xảy ra <=> x + 1 = 0

=> x = - 1

Vậy Max C = 12 <=> x = - 1

d) Ta có  D =  -2|x + 4| + 5 = 5 - 2|x + 4| 

Lại có \(2\left|x+4\right|\ge0\forall x\Rightarrow5-2\left|x+4\right|\le5\forall x\)

Dấu "=" xảy ra <=> x + 4 = 0

=> x = - 4

Vậy Max D = 5 <=> x = -4

\(a)\frac{3^{10}.\left(-5\right)^{21}}{\left(-5\right)^{20}.3^{12}}=\frac{-5}{3^2}=\frac{-5}{9}\)

\(b)\frac{-11.13^7}{11^5.13^8}=\frac{-1}{11^4.13}\) (Bạn xem thử xem có sai đề không nhé)

\(c)\frac{2^{10}.3^{10}-2^{10}.3^9}{2^9.3^{10}}=\frac{2^{10}.3^9\left(3+1\right)}{2^9.3^{10}}=\frac{2.4}{3}=\frac{8}{3}\)

\(d)\frac{5^{11}.7^{12}+5^{11}.7^{11}}{5^{12}.7^{12}+9.5^{11}.7^{11}}=\frac{5^{11}.7^{11}\left(7+1\right)}{5^{11}.7^{11}\left(5.4+9\right)}=\frac{8}{20+9}=\frac{8}{29}\)

\(a)\frac{3^{10}\cdot\left(-5\right)^{21}}{\left(-5\right)^{20}\cdot3^{12}}=\frac{-5}{3^2}=\frac{-5}{9}\)

\(b)\frac{\left(-11\right)\cdot13^7}{11^5\cdot13^8}=\frac{-1}{11^4\cdot13}=\frac{-1}{14641\cdot13}=\frac{-1}{190333}\)

\(c)\frac{2^{10}\cdot3^{10}-2^{10}\cdot3^9}{2^9\cdot3^{10}}=\frac{2^{10}\left(3^{10}-3^9\right)}{2^9\cdot3^{10}}=\frac{2^{10}\cdot3^9\left(3-1\right)}{2^9\cdot3^{10}}=\frac{2^{10}\cdot3^9\cdot2}{2^9\cdot3^{10}}=\frac{2\cdot2}{3}=\frac{4}{3}\)

=45 nha

olm duyet di

= 45

tích nha!!!..^.^

b)-5/12 . 2/11+(-5/12) . 9/11+5/12

=(-5/12+5/12).(2/11+9/11)

=0.1=0

c)6/9/10+(2/5-1/10)

=69/10+3/10

=36/5

\(b)\)\(\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}\)

\(=\frac{-5}{12}.\frac{2}{11}+\frac{-5}{12}.\frac{9}{11}+\frac{5}{12}.1\)

\(=\frac{-5}{12}.\left(\frac{2}{11}+\frac{9}{11}+1\right)\)

\(=\frac{-5}{12}.2\)

\(=\frac{-5}{6}\)

\(c)\)\(6\frac{9}{10}+\left(\frac{2}{5}-\frac{1}{10}\right)\)

\(=6\frac{9}{10}+\frac{2}{5}-\frac{1}{10}\)

\(=\left(6\frac{9}{10}-\frac{1}{10}\right)+\frac{2}{5}\)

\(=6\frac{4}{5}+\frac{2}{5}\)

\(=6\frac{6}{5}=7\frac{1}{5}\)