`a, 9^8 : 9^3 : 3^4`

`= 9^8 : 9^3 : 9^2`

`= 9^(8-3-2)= 9^3`.

`b, x . 4x . 16x . 64x`

`= x. 4x . 4^2x . 4^3x`

`= 4^6x^4`

9^8:3^2=(3^2)^8:3^2=3^16:3^2=3^16-2=3^14

9^8:3^2=9^8:9=9^7 

9^8=43046721

3^2=9

k mk nha!

9⁸:3²

=9⁸:9

=9⁷

^{tk nha~~~~~~~~~~~~~~~~~}

thanks

9⁸ : 3² = 9⁸ : 9¹ = 9^8-1= 9⁷

~HT~

9⁸= 9.9.9.9.9.9.9.9= 43046721

3²= 3.3= 9

43046721 : 9 = 4782969

\(9^8:3^2\)

\(=\left(3^2\right)^8:3^2\)

\(=3^{16}:3^2\)

\(=3^{14}\)

9^8:3^2

= (3^2)^8 : 3^2

= 3^16 : 3^2

=3^14

\(9^8:3^2=\left(3^2\right)^8:3^2=3^{16}:3^2=3^{\left(16-2\right)}\)

---Học tốt---

ta có : \(4^3.3^7.12^6.9^3.8^2=\left(2^2\right)^3.3^7.\left(2^2.3\right)^6.\left(3^2\right)^3.\left(2^3\right)^2\)

= \(2^6.3^7.2^{12}.3^6.3^6.2^6=2^{24}.3^{19}\)

\(4^3.3^7.12^6.9^3.8^2=2^6.3^7.2^{12}.3^6.3^6.2^6=2^{24}.3^{19}\)

Đề này là chịu rồi

Ta có: 4³ . 3⁷ . 12⁶ . 9³ . 8²

= (2²)³ . 3⁷ . (4 . 3)⁶ . (3²)³ . (2³)²

= 2⁶ . 3⁷ . 4⁶ . 3⁶ . 3⁶ . 2⁶

= 2⁶ . 3⁷ . (2²)⁶ . 3⁶ . 3⁶ . 2⁶

= 2⁶ . 3⁷ . 2¹² . 3⁶ . 3⁶ . 2⁶

= (2⁶ . 2¹² . 2⁶) . (3⁷ . 3⁶ . 3⁶)

= 2²⁴ . 3¹⁹

Chuk pạn hok tốt! 

\(\dfrac{9^{85}}{\left(-3\right)^{40}}=\dfrac{9^{85}}{3^{40}}=\dfrac{3^{255}}{3^{40}}=3^{215}\)

\(\frac{9^{85}}{(-3)^{40}}= \frac{\left [ (3)^{2} \right ]^{85}}{3^{40}}= \frac{3^{170}}{3^{40}}= 3^{130}\)

\(3^8\cdot2^7\)

\(=3^7\cdot2^7\cdot3\)

\(=\left(3\cdot2\right)^7\cdot3=6^7\cdot3\)

\(=839808\)

\(3^8\times2^7=3^7\times3\times2^7=\left(3\times2\right)^7\times3=6^7\times3\)