Question

so sánh x=2^30+3^30+4^30 và y=3^20 +6^20+8^20

Answer 1

cứu tui 

Answer 2

Ta có:\(2^{30}=\left(2^3\right)^{10}=8^{10}< 9^{10}=\left(3^2\right)^{10}=3^{20}\)

\(3^{30}=3^{20}.3^{10}< 3^{20}.4^{10}=3^{20}.\left(2^2\right)^{10}=3^{20}.2^{20}=\left(3.2\right)^{20}=6^{20}\)

\(4^{30}=4^{20}.4^{10}=4^{20}.\left(2^2\right)^{10}=4^{20}.2^{20}=\left(4.2\right)^{20}=8^{20}\)

nên \(2^{30}+3^{30}+4^{30}< 3^{20}+6^{20}+8^{20}\)

Answer 3

Ta có : x=2³⁰ + 3³⁰ + 4³⁰

x=2^3.10 + 3^3.10 + 4^3.10

x=(2³)²⁰ + (3³)¹⁰ + (4³)¹⁰

x=8²⁰ + 9¹⁰ + 64¹⁰

y=3²⁰ + 6²⁰ + 8²⁰

y=3^2.10 + 6^2.10 + 8^2.10

y=(3²)¹⁰ + (6²)¹⁰ + (8²)¹⁰

y=9¹⁰ + 36¹⁰ + 64¹⁰

mà 9¹⁰ > 8²⁰ ;36¹⁰ >9¹⁰ ;64¹⁰ = 64¹⁰

nên x<y