8^5=32768<3*4^7=49152

8⁵ = (2³)⁵ = 2¹⁵; 3 x 4⁷ < 4.4⁷ = 4⁸ = (2²)⁸ = 2¹⁶

Vậy  2¹⁵ < 2¹⁶

  8⁵ < 3 x 4⁷

8⁵=32768

3x4⁷=49152

=>8⁵<3x4⁷

125⁵=30517578125

25⁷=6103515625

=>125⁵>25⁷

Cách ngắn hơn nè:

125^5 và 25^7

Ta có: 125^5= (5^3)^5= 5^15

25^7= (5^2)^7= 5^14

Vì 5^15>5^14 nên 125^5>25^7

Ta có: \(\frac{5-4}{2\times3}+\frac{6-5}{3\times4}+\frac{8-7}{4\times5}+\frac{9-8}{5\times6}\)

\(=\frac{1}{2\times3}+\frac{1}{3\times4}+\frac{1}{4\times5}+\frac{1}{5\times6}\)

\(=\frac12-\frac13+\frac13-\frac14+\frac14-\frac15+\frac15-\frac16=\frac12-\frac16=\frac13\)

\(5\dfrac{1}{3}\times\dfrac{4}{7}:\dfrac{3}{8}\)

\(=\dfrac{16}{3}\times\dfrac{4}{7}\times\dfrac{8}{3}\)

\(=\dfrac{16\times4\times8}{3\times7\times3}\)

\(=\dfrac{512}{63}\)

a) 2.2¹⁴ < 3.2¹⁴

b) (99+1)²⁰ ; (9999+1)¹⁰= 10000¹⁰= 100²⁰

=> 99²⁰ = 9999¹⁰

IQ<95 hiu chit lien

chúc mung bn linh-kun, bn hiu dc chung to IQcua bn>95

a) 8⁵ < 3x4⁷                                                                                         b) 2009²⁰¹⁰ + 2009²⁰⁰⁹ > 2010²⁰¹⁰

a, \(\dfrac{20}{15}=\dfrac{4}{3}\)

b, \(\dfrac{6}{15}=\dfrac{2}{5}\)

c, \(\dfrac{42}{30}=\dfrac{7}{5}\)

d, \(\dfrac{40}{35}=\dfrac{8}{7}\)

e, \(\dfrac{42}{42}=1\)

g, \(\dfrac{54}{10}=\dfrac{27}{5}\)

h, \(\dfrac{12}{15}\)

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