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20 tháng 6 2017

a) $3^8:3^6=3^{8-6}=3^2$

$19^7:19^3=19^{7-3}=19^4$

$2^{10}:8^3=2^{10}:(2^3)^3=2^{10}:2^9=2^{10-9}=2^1$

$12^7:6^7=(12:6)^7=2^7$

$27^5:81^3=(3^3)^5:(3^4)^3=3^{15}:3^{12}=3^{15-12}=3^3$

b) $10^6:10=10^{6-1}=10^5$

$5^8:25^2=5^8:(5^2)^2=5^8:5^4=5^{8-4}=5^4$

$4^9:64^2=4^9:(4^3)^2=4^9:4^6=4^{9-6}=4^3$

$2^25:32^4=2^{25}:(2^5)^4=2^{25}:2^{20}=2^{25-20}=2^5$

$18^3:9^3=(18:9)^3=2^3$

20 tháng 6 2017

\(\cdot3^8:3^6=3^{8-6}=3^2\)

\(\cdot19^7:19^3=19^{7-3}=19^4\)

\(\cdot2^{10}:8^3=2^{10}:\left(2^3\right)^3=2^{10}:2^9=2\)

\(\cdot12^7:6^7=\left(12:6\right)^7=2^7\)

\(\cdot27^5:81^3=\left(3^3\right)^5:\left(3^4\right)^3=3^{15}:3^{12}=3^3\)

\(\cdot10^6:10=10^{6-1}=10^5\)

\(\cdot5^8:25^2=5^8:\left(5^2\right)^2=5^8:5^4=5^4\)

\(\cdot4^9:64^2=4^9:\left(4^3\right)^2=4^9:4^6=4^3\)

\(2^{25}:32^4=2^{25}:\left(2^5\right)^4=2^{25}:2^{20}=2^5\)

\(18^3:9^3=\left(18:9\right)^3=2^3\)

30 tháng 6 2015

a) Có các số: 10^2; 11^2 ; 12^2 ;13^2; 14^2

Tức có 5 số chính phương từ 100 đến 200 là 100;121;144;169;196.

 Tổng các số đó: 100 + 121 + 144 + 169 + 196 = 730

9 tháng 7 2016

\(\frac{45^7.9^3.27^{12}.12^8}{2^{26}.5^{14}.3^{16}.81^2}=\frac{\left(3^2\right)^7.5^7.\left(3^2\right)^3.\left(3^3\right)^{12}.\left(2^2\right)^8.3^8}{2^{26}.5^{14}.3^{16}.\left(3^4\right)^2}=\frac{3^{14}.5^7.3^6.3^{36}.2^{16}.3^8}{2^{26}.5^{14}.3^{16}.3^8}\)

\(=\frac{3^{64}.5^7.2^{16}}{2^{26}.5^{14}.3^{24}}=\frac{3^{40}.1.1}{2^{10}.5^7.1}=\frac{3^{40}}{2^{10}.5^7}\)

12 tháng 5 2015

=> [3x-7/9]^3= -8/27

=> 3x -7/9 = -2/3 => 3x = 1/9=> x= 1/27

đúng cái nhé

16 tháng 1 2018

a/ \(\left(-19\right)+5+\left(-8\right)+19+\left(-3\right).\left(-2\right)^3\)

\(\left(-19\right)+5+\left(-8\right)+19+\left(-3\right).\left(-8\right)\)

\(\left(-19\right)+5+\left(-8\right)+19+24\)

\(\left(-14\right)+11+24\)

\(\left(-3\right)+24=21\)

b/ \(\left(-5\right)^3-\left(3^3+4\right).\left(-2\right)+\left(3-27\right):4\)

\(\left(-125\right)-\left(27+4\right).\left(-2\right)+\left(3-27\right):4\)

\(\left(-125\right)-\left(31\right).\left(-2\right)+\left(-24\right):\text{4}\)

\(\left(-125\right)-\left(-62\right)+\left(-6\right)\)

\(\left(-63\right)+\left(-6\right)=-69\)

c/ \(\left[504-\left(5^2.8+70\right):3^2+6\right]:\left(-20\right)\)

\(\left[504-\left(25.8+70\right):9+6\right]:\left(-20\right)\)

\(\left[504-270:9+6\right]:\left(-20\right)\)

\(\left[504-30+6\right]:\left(-20\right)\)

\(480:\left(-20\right)=-24\)

d/ \(\left(-7\right)-\left[\left(-19\right)+21\right].\left(-3\right)-\left[32+\left(-7\right)\right]\)

\(\left(-7\right)-2.\left(-3\right)-25\)

\(\left(-7\right)-\left(-6\right)-25\)

\(\left(-1\right)-25=-26\)

\(\)

4 tháng 8 2015

1. A - B = 40+ 3/8 + 7/8+ 5/83 + 32/85 - (24/82 + 40+ 5/82 + 40/84 + 5/84 )

= 40.85/85 + 3.84/85 + 7.83/85 + 5.82/85 + 32/85 - 24.83/85 - 40.85/85 - 5.83/85 - 40.8/85 - 5.8/85

= 40.85/85 + 24.83/85 + 7.83/85 + 5.82/85 + 32/85 - 24.83/85 - 40.85/85 - 5.83/85 - 40.8/85 - 5.8/85

= 7.83/85 + 5.82/85 + 32/85 - 5.83/85 - 40.8/85 - 5.8/85

= 7.83/85 + 5.82/85 -8/85 - 5.83/85 - 40.8/85

= 2.83/85 + 5.82/8- 40.8/85 - 8/85

= 2.83/85 + 40.8/8- 40.8/85 - 8/85

= 2.83/8 - 8/85 > 0 

Vay A > B

15 tháng 3 2017

ai so sanh C va D di ma duoc thi minh se tink cho