Đáp án là A

Ta có: (368 + 764) - (363 + 759) = (368 - 363) + (764 - 759)

     = 5 + 5 = 10

Đáp án cần chọn là: A

Ta có (368+764)−(363+759)= 1132–1122=10

 ( 764 - 759 ) + ( 368 - 369 ) 

= 5 - 5 = 10 

b) ( 4172 - 4168 ) - (1873 - 1869 ) 

= 4-4 = 0

\(=368+764-368-759=\left(368-368\right)+\left(764-759\right)=0+5=5\)

\(\left(368+764\right)-\left(368+759\right)\)

\(=368+764-368-759\)

\(=\left(368-368\right)+\left(764-759\right)\)

\(=0+5=5\)

a=240

b=45

c=-1700

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: \(3^{99}>11^{21}\)

Chọn A