Bài 1: Viết các biểu thức sau dưới dạng lũy thừa của 1 số:
a) \(\frac{21^{30}}{63^{15}}\) b) \(\frac{28^9.30^9}{105^9}\)
Bài 2: Tính giá trị của các biểu thức sau:
a) \(\frac{\left(5^5-5^4\right)^3}{50^6}\) b) \(\frac{32^3.9^5}{8^3.6^6}\)
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Ta có :
a) \(\frac{21^{30}}{63^{15}}=\frac{\left(21^2\right)^{15}}{63^{15}}=\left(\frac{21^2}{63}\right)^{15}\)
b) \(\frac{28^9.30^9}{105^9}=\frac{\left(28.30\right)^9}{105^9}=\frac{840^9}{105^9}=\left(\frac{840}{105}\right)^9=8^9\)
a) \(8^{15}.4^{13}=\left(2^3\right)^{15}.\left(2^2\right)^{13}=2^{45}.2^{26}=2^{71}\)
b) \(\left(\frac{1}{2}\right)^{18}.\left(\frac{1}{4}\right)^{28}=\left(\frac{1}{2}\right)^{18}.\left(\frac{1}{2^2}\right)^{28}=\frac{1}{2^{18}}.\frac{1}{2^{56}}=\frac{1}{2^{74}}=\left(\frac{1}{2}\right)^{74}\)
c) \(9^{12}.27^{10}=\left(3^2\right)^{12}.\left(3^3\right)^{10}=3^{24}.3^{30}=3^{54}\)
a) = (23)15. (22)13 = 245.226 = 271
b) = \(\left(\frac{1}{2}\right)^{18}.\left(\left(\frac{1}{2}\right)^2\right)^{28}=\left(\frac{1}{2}\right)^{18}.\left(\frac{1}{2}\right)^{56}=\left(\frac{1}{2}\right)^{18+56}=\left(\frac{1}{2}\right)^{74}\)
c) = (32)12.(33)10 = 324.330 = 324+30 = 354
a. 82. 324 = 26. 220 = 226
b. 273. 94. 243 = 39. 38. 35 = 322
c. 5 .125 . 625 = 5 . 53. 54 = 58
d.10 . 100 . 1000 = 10 . 102. 103 = 106
e. 84. 165. 32 = 212. 220. 25 = 237
f. 274 . 8110 = 312. 340 = 352
\(\frac{8^{11}.3^{17}}{27^{10}.9^{15}}=\frac{8^{11}.3^{17}}{3^{30}.3^{30}}=\frac{8^{11}}{3^{13}.3^{30}}=\frac{8^{11}}{3^{43}}\)
\(\frac{\left(5^4-5^3\right)^3}{125^4}=\frac{[\left(5-1\right).5^3]^3}{5^{12}}=\frac{\left(4.5^3\right)^3}{5^{12}}=\frac{64.5^9}{5^{12}}=\frac{64}{5^3}=\left(\frac{4}{5}\right)^3\)
\(\frac{4^{20}-2^{20}+6^{20}}{6^{20}-3^{20}+9^{20}}=\frac{2^{40}-2^{20}+6^{20}}{6^{20}-3^{20}+3^{40}}=\frac{2^{20}.\left(2^{20}-1+3^{30}\right)}{3^{20}.\left(2^{20}-2+3^{20}\right)}=\frac{2^{20}}{3^{20}}=\left(\frac{2}{3}\right)^{20}\)
Bài 1:
a) \(4^8\cdot2^{20}=\left(2^2\right)^8\cdot2^{20}=2^{36}\)
\(64^3\cdot4^5=\left(2^6\right)^3\cdot\left(2^2\right)^5=2^{18}\cdot2^{10}=2^{28}\)
\(y\cdot y^7=y^{1+7}=y^8\)
\(a^n\cdot a^2=a^{n+2}\)
Bài 1:
b) \(10^8:2^8=5^8\)
\(17^8:17^5=17^3\)
\(2^{25}:32^4=2^{25}:2^{20}=2^5\)
\(19^4:9^4=\left(\dfrac{19}{9}\right)^4\)
\(4^{10}\cdot8^{15}\)
\(=\left(2^2\right)^{10}\cdot\left(2^3\right)^{15}\)
\(=2^{20}\cdot2^{45}\)
\(=2^{30+45}\)
\(=2^{75}\)
\(a;4^{10}\cdot8^{15}=2^{20}\cdot2^{45}=2^{65}\)
\(b;4^{15}\cdot5^{30}=2^{30}\cdot5^{30}=10^{30}\)
a) 158 x 94
= 158 x ( 32 )4
= 158 x 38
= ( 15 x 3 )8 = 458
b) 49 : 527
= 49 : ( 53 ) 9
= 49 : 1259
= \(\left(\frac{4}{125}\right)^9\)
c) 2010 : 220
= 2010 : ( 22 )10
= 2010 : 410 = ( 20 : 4 ) 10 = 510
d) 275 : ( -7 ) 15
= 275 : [ ( - 7 )3 ]5
= 275 : ( - 21 )5
= \(\left(\frac{27}{-21}\right)^5=\left(\frac{9}{-7}\right)^5\)
Cbht