Câu 1.99²⁰và 9999¹⁰

⁼(99²)¹⁰=9801¹⁰

Vậy 9801¹⁰<9999¹⁰ suy ra  99²⁰<9999¹⁰

Câu 2. 3⁵⁰⁰và 7³⁰⁰

 3⁵⁰⁰=(3⁵)¹⁰⁰=243¹⁰⁰

7³⁰⁰=(7³)¹⁰⁰=343¹⁰⁰

Vậy 243¹⁰⁰<343¹⁰⁰ => 3⁵⁰⁰<7³⁰⁰

a)3⁵⁰⁰ = (3⁵)¹⁰⁰ = 243¹⁰⁰

7³⁰⁰ = (7³)¹⁰⁰ = 343¹⁰⁰

243¹⁰⁰ < 343¹⁰⁰ => 3⁵⁰⁰ < 7³⁰⁰

Lời giải:
$1990^{10}+1990^9=1990^9(1990+1)=1991.1990^9< 1991.1991^9=1991^{10}$

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$10^{10}=(10^2)^5=100^5=(2.50)^5=2^5.50^5=32.50^5< 48.50^5$

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$11^{1979}< 11^{1980}=(11^3)^{660}=1331^{660}$
$37^{1320}=(37^2)^{660}=1369^{660}> 1331^{660}$

$\Rightarrow 11^{1979}< 37^{1320}$

b: 99^20=(99^2)^10=9801^10

=>99^20<9999^10

d: 10^10=100^5=4*50^5<48*50^5

e: 1990^10+1990^9

=1990^9(1990+1)

=1990^9*1991

1991^10=1991^9*1991

=>1991^10>1990^9*1991

=>1991^10>1990^10+1990^9

f: 11^1979<11^1980=1331^660

37^1320=(37^2)^660=1369^660

1331<1369

=>1331^660<1369^660

=>11^1980<37^1320

=>11^1979<37^1320

g: 10^10=2^10*5^10

48*50^5=2^4*3*2^5*5^10=2^9*3*5^10

2^10<2^9*3

=>2^10*5^10<2^9*3*5^10

=>10^10<48*50^5

a) 5\(^{30}\) > 124\(^{10}\) b) 9\(^{21}\)= 729\(^7\) c)31\(^{11}\)> 17\(^{14}\)

d) không biết e)<

a)1990¹⁰+1990⁹=1990⁹(1990+1)=1990⁹x1991

1991¹⁰=1991⁹x1991

Vì 1991⁹>1990⁹=>1991⁹x1991>1990⁹x1991

b)2⁹¹=128¹³=128¹¹x128²

5³⁵=125¹¹:5

=>128¹¹>125¹¹

=>128¹¹x128²>125¹¹:5

c)5²³=5²².5

vì 5²²=5²²

=>5²².5<5²².6