Gồm các số : 1110 ; 1101 ; 1011 ; 2100 ; 2010 ; 2001 ; 1200 ; 1020 ; 1002 ; 3000.

Thanks

Ta có :

a) 199²⁰ = ( 1994 )⁵

2003¹⁵ = ( 2003³ )⁵

Vì 199⁴ < 2003³ => ( 199⁴ )5 < ( 2003³ )⁵

=> 199²⁰ < 2003¹⁵

b) 3⁹⁹ = 3³³ )³ 

11²¹ = ( 11⁷ )³

Vì 3³³ > 11⁷

=> ( 3³³ )³ > ( 11⁷ )³

=> 3⁹⁹ > 11²¹

c) Vì 5⁴⁰ = ( 5⁴ )¹⁰ = 625¹⁰ > 620¹⁰

=> 5⁴⁰ > 620¹⁰

d) 3⁴⁸⁴ = ( 3⁴ )¹²¹ = 81¹²¹

4³⁶³ = ( 4³ )¹²¹ = 64¹²¹

Vì 81¹²¹ > 64¹²¹ => 3⁴⁸⁴ > 4³⁶³

So sánh:

\(a)\)\(199^{20}\) và   \(2003^{15}\)

\(\Rightarrow\)\(199^{20}< 200^{20}=\left(2^3.5^2\right)^{20}=2^{60}.5^{40}\)

\(\Rightarrow\)\(2003^{15}>2000^{15}=\left(2.10^3\right)^{15}=\left(2^4.5^3\right)^{15}=2^{60}.5^{45}\)

Vì: \(2^{60}.5^{40}< 2^{60}.5^{45}\)

Nên: \(199^{20}< 2003^{15}\)

\(b)\)\(3^{99}\)và     \(11^{21}\)

\(3^{99}=\left(3^{33}\right)^3\)

\(11^{21}=\left(11^7\right)^3\)

Vì: \(\left(3^{33}\right)^3>\left(11^7\right)^3\)

Nên: \(3^{99}>11^{21}\)

2 thg 11, 2018 — a, x^2-y^2-x+y= (x^2-y^2)-(x-y)=(x-y)(x+y)-(x-y)=(x-y)(x+y-1). b, x^4-x^3-x^2+1=(x^4-x^3)-(x^2-1)=x^3(x-1)-(x-1)(x+1)=(x-1)(x^3-x-1).

x² - y² + x-y

= (x-y)(x+y) + (x-y)

= (x-y)(x+y+1)

Bài 1: 

a, \(\dfrac{-x-2}{3}\) = - \(\dfrac{6}{7}\)

      - \(x\) - 2 = - \(\dfrac{18}{7}\)

         \(x\)      = - 2 + \(\dfrac{18}{7}\)

         \(x\)      = - \(\dfrac{4}{7}\)

Bài b,  \(\dfrac{4}{7-x}\) = \(\dfrac{1}{3}\)

            12 = 7 - \(x\)

            \(x\)  = 7 - 12 

            \(x\)  = -5 

Bài 2 :

a) 3⁷ . 27⁵ . 81³

= 3⁷ . ( 3³ )⁵ . ( 3⁴ )³

= 3⁷ . 3¹⁵ . 3¹²

= 3³⁴

b) 36⁵ : 18⁵

= ( 36 : 18 )⁵

= 2¹⁵

c) 24 . 5⁵ + 5² . 5³

= 24 . 5⁵ + 5⁵

= 5⁵ . ( 24 + 1 )

= 5⁵ . 25 

= 5⁵ . 5²

= 5⁷

d) 125⁴ : 5⁸

= ( 5³ )⁴ : 5⁸

= 5¹² : 5⁸

= 5⁴

CẢM ƠN BẠN NHA