\(\frac{2^8}{8^9}\cdot\frac{12^9}{81^2}\\ =\frac{2^8}{\left(2^3\right)^9}\cdot\frac{\left(2^2\cdot3\right)^9}{\left(3^4\right)^2}\\ =\frac{2^8}{2^{27}}\cdot\frac{2^{18}\cdot3^9}{3^8}\\ =\frac{2^8\cdot2^{18}\cdot3^9}{2^{27}\cdot3^8}\\ =\frac{2^{26}\cdot3^9}{2^{27}\cdot3^8}\\ =\frac{3}{2}\)
so sanh
(-1/16) mu 100 va (-1/2) mu 500
(1/81) mu 12 va (1/27) mu 16
(-2) mu 10 va 1000
2 mu 93 va 5 mu 35
1 tính
a. \((\left|-5\right|7^4+3^2.2\dfrac{2}{5}):(7^5.125.7^3.50)\)
b. \((\dfrac{3^2}{9}.\dfrac{3^3}{81})^{12}:(\dfrac{3^6}{81^2})^{10}\)
c. \([(\dfrac{1}{2})^2.(\dfrac{1}{3})^4.\dfrac{2}{7}]:\left(\dfrac{1}{3}\right)^{-2}.\dfrac{-2^2}{7}\)
Câu 1: Rút gọn các biểu thức sau:
C = \(\dfrac{8^2.9^5}{3^9.4^3}\)
D = \(\dfrac{81^6.9^5}{27^7.3^{11}}\)
F = \(\dfrac{8^{15}.25^7}{125^5.2^{47}}\)
G = \(\dfrac{10^2.5^3}{8.25^2}\)
Chứng minh rằng
a) (8^7-2^18) chia hết cho 14
b) (81^7-27^9-9^13) chia hết cho 15
Tìm số tự nhiên n, biết :
a) \(\dfrac{16}{2^n}=2\)
b) \(\dfrac{\left(-3\right)^n}{81}=-27\)
c) \(8^n:2^n=4\)
a. \(\dfrac{81}{3^{2x+1}}=3\)
b.\(2^x+2^{x+2}=80\)
c.\(\dfrac{16^{x+2}}{8^x}=4^5\)
d. \(2^x+2^{x+1}+2^{x+2}=112\)
1.So sánh các cặp số sau:
a) 12^8 và 8^12 b) (-5)^39 và (-2)^91
Các bạn giúp mình với!
a) 125\(^3\).7\(^4\) - 5\(^9\). 49\(^2\) : 2005\(^{2006}\)
b) 64\(^2\).81\(^3\).34 : 2\(^{13}\).3\(^9\).17
c) 16.64.8\(^2\) : 4\(^3\).2\(^5\).16
d) 10. \(\frac{4^6.9^5+6^9.120}{8^4.3^{12}-6^{11}}\)
chung minh rang
a, \(7^8+7^7-7^6⋮55\)
b ,\(16^5+2^{15}⋮33\)
c, \(81^7-27^9-9^{13}⋮405\)
