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21 tháng 12 2018

a) 

7-x-25-7=-25

-x-25=-25

-x=0

x=0

b)

(3x-24).73=2.74

3x-24 = 2.74 : 73 = 2.74-3=2.7=14

3x-16=14

3x=14+16=30

x=30:3=10

cảm ơn

25 tháng 7 2017

a)(357.252.714):510=(57.77.54.714):510=(511.721):510=5.721

b)=215.520.212.54 /22.52=227.524/22.52=225.522

16 tháng 11 2016

Giúp mình với

28 tháng 9 2016

2.009765625x\(10^{10}\)

25 tháng 9 2016

a) \(4^{10}.2^{30}=\left(2^2\right)^{10}.2^{30}=2^{2.10}.2^{30}=2^{20}.2^{30}=2^{20+30}=2^{50}\)

b) \(9^{25}.27^4.81^3=\left(3^2\right)^{25}.\left(3^3\right)^4.\left(3^4\right)^3=3^{3.25}.3^{3.4}.3^{4.3}=3^{75}.3^{12}.3^{12}=3^{75+12+12}=3^{99}\)

c) \(25^{50}.125^5=\left(5^2\right)^{50}.\left(5^3\right)^5=5^{2.50}.5^{3.5}=5^{100}.5^{15}=5^{100+15}=5^{115}\)

d) \(64^3.4^8.16^4=\left(4^3\right)^3.4^8.\left(4^2\right)^4=4^{3.3}.4^8.4^{2.4}=4^9.4^8.4^8=4^{9+8+8}=4^{25}\)

25 tháng 9 2016

e) \(3^8:3^6=3^{8-6}=3^2\)

f)  \(2^{10}:8^3=2^{10}:\left(2^3\right)^3=2^{10}:2^{3.3}=2^{10}:2^9=2^{10-9}=2\)

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

h_ \(21^5:81^3\)kết quả là số dư nên không tính ( đề sai )

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

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

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

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

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

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

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

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

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

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

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

7 tháng 7 2018

\(\left(\frac{3}{7}+\frac{1}{2}\right)^2=\left(\frac{13}{14}\right)^2=\frac{169}{196}\)

\(\frac{5^4\cdot20^4}{25^5\cdot4^5}=\frac{5^4\cdot4^4\cdot5^4}{5^5\cdot5^5.4^5}=\frac{1}{100}\)

\(\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{49}\right)^6=\left(\frac{3}{7}\right)^{21}:\left[\left(\frac{3}{7}\right)^2\right]^6=\left(\frac{3}{7}\right)^{21}:\left(\frac{3}{7}\right)^{12}=\left(\frac{3}{7}\right)^9\)

\(3-\left(-\frac{6}{7}\right)^0+\left(\frac{1}{2}\right)^2:2\)

\(=3-1+\frac{1}{4}:2=3-1+\frac{1}{8}=\frac{17}{8}\)