a) \(12^8=\left(12^2\right)^4=144^4\)

     \(8^{12}=\left(8^3\right)^4=512^4\)

Vì \(144^4< 512^4\Rightarrow12^8< 8^{12}\)

Vậy \(12^8< 8^{12}\)

b) \(\left(-5\right)^{39}=\left[\left(-5\right)^3\right]^{13}=\left(-125\right)^{13}\)

     \(\left(-2\right)^{91}=\left[\left(-2\right)^7\right]^{13}=\left(-128\right)^{13}\)

Vì \(\left(-125\right)^{13}>\left(-128\right)^{13}\Rightarrow\left(-5\right)^{39}>\left(-2\right)^{91}\)

Vậy \(\left(-5\right)^{39}>\left(-2\right)^{91}\)

bài này mik làm đc rùi,khỏi trả lời nhá 

a , ta có : 8¹² = ( 4 . 2 )¹² = 4²⁴

12⁸ = ( 4 . 3 ) ⁸ = 4²⁴

vì 24 = 24 nên 4^24 = 4^24

do đó 8^12 = 12^8 ..

K BIẾT CÓ ĐÚNG K NỮA

AI K MIK MIK K LẠI

a)\(12^8=\left(12^2\right)^4=144^4\)

\(8^{12}=\left(8^3\right)^4=512^4\)

\(144^4< 512^4\Rightarrow12^8< 8^{12}\)

b)\(\left(-5\right)^{39}=\left[\left(-5\right)^3\right]^{13}=\left(-125\right)^{13}\)

\(\left(-2\right)^{91}=\left[\left(-2\right)^7\right]^{13}=\left(-128\right)^{13}\)

\(\left(-125\right)^{13}>\left(-128\right)^{13}\Rightarrow\left(-5\right)^{39}>\left(-2\right)^{91}\)

1) Ta có:

12⁸ = (2².3)⁸ = 2¹⁶.3⁸

8¹² = (2³)¹² = 2³⁶ = 2¹⁶.2²⁰ = 2¹⁶.(2²)¹⁰ = 2¹⁶.4¹⁰

Vì 2¹⁶.3⁸ < 2¹⁶.4¹⁰

=> 12⁸ < 8¹²

2) Ta có:

(-5)³⁹ = -5³⁹ = -(5³)¹³ = -125¹³

(-2)⁹¹ = -2⁹¹ = -(2⁷)¹³ = -128¹³

Vì -125¹³ > -128¹³

=> (-5)³⁹ > (-2)⁹¹

a/ Ta có :

\(12^8=\left(12^2\right)^4=144^4\)

\(8^{12}=\left(8^3\right)^4=512^4\)

Vì \(144^4< 512^4\Leftrightarrow12^8< 8^{12}\)

b/ Ta có :

\(\left(-5\right)^{39}=\left[\left(-5\right)^3\right]^{13}=\left(-125\right)^{13}\)

\(\left(-2\right)^{91}=\left[\left(-2\right)^7\right]^{13}=\left(-128\right)^{13}\)

Vì \(\left(-125\right)^{13}< \left(-128\right)^{13}\Leftrightarrow\left(-5\right)^{39}< \left(-2\right)^{91}\)

a) 12^8 = (12^2)^4 =144^4

8^12 = (8^3)^4= 512^4

Vì 144 < 512 nên 144^4<512^4

Vậy 12^8 < 8^12

a/ Ta có :

\(12^8=\left(12^2\right)^4=24^4\)

\(8^{12}=\left(8^3\right)^4=512^4\)

Vì \(24^4< 512^4\Leftrightarrow12^8< 8^{12}\)

b/ \(\left(-5\right)^{39}=\left[\left(-5\right)^3\right]^{13}=\left(-125\right)^{13}\)

\(\left(-2\right)^{91}=\left[\left(-2\right)^7\right]^{13}=\left(-128\right)^{13}\)

Vì \(\left(-125\right)^{13}>\left(-128\right)^{13}\Leftrightarrow\left(-5\right)^{39}>\left(-2\right)^{91}\)

a)Ta có :

\(12^8=12^{2.4}=\left(12^2\right)^4=144^4\)

\(8^{12}=8^{3.4}=\left(8^3\right)^4=512^4\)

Mà 512>144 nên \(512^4>144^4\)

Vậy \(8^{12}>12^8\)

ngu như con lợn

a)Ta có:12⁸=(12²)⁴=144⁴

              8¹²=(8³)⁴=512⁴

         Vì 144⁴<512⁴

                   Suy ra:12⁸<8¹²

b)Ta có:(-5)³⁹=[(-5)³]¹³=(-125)¹³

             (-2)⁹¹=[(-2)⁷]¹³=(-128)¹³

          Vì (-128)¹³<(-125)¹³

                      Suy ra:(-2)⁹¹<(-5)³⁹

\(a.\)  \(12^8\)  và  \(8^{12}\)

Ta có : 

\(12^8=\left(12^2\right)^4=114^4\)

\(8^{12}=\left(8^3\right)^4=512^4\)

Vì   \(114^4< 512^4\)  nên  \(12^8< 8^{12}\)

Vậy :        \(12^8< 8^{12}\)

\(b.\)  \(\left(-5\right)^{39}\)  và  \(\left(-2\right)^{91}\)

Ta có : 

\(\left(-5\right)^{39}=\left(-5^3\right)^{13}=\left(-125\right)^{13}\)

\(\left(-2\right)^{91}=\left(-2^7\right)^{13}=\left(-128\right)^{13}\)

Vì  \(\left(-125\right)^{13}>\left(-128\right)^{13}\)  nên  \(\left(-5\right)^{39}>\left(-2\right)^{91}\)

a/ Ta có :

\(12^8=\left(12^2\right)^4=24^4\)

\(8^{12}=\left(8^3\right)^4=512^4\)

Vì \(24^4< 512^4\Leftrightarrow12^8< 8^{12}\)

b/ Ta có :

\(\left(-5\right)^{39}=\left[\left(-5\right)^3\right]^{13}=\left(-125\right)^{13}\)

\(\left(-2\right)^{91}=\left[\left(-2\right)^7\right]^{13}=\left(-128\right)^{13}\)

Vì \(\left(-125\right)^{13}>\left(-128\right)^{13}\Leftrightarrow\left(-5\right)^{39}>\left(-2\right)^{91}\)