8 x 8 = 8²

9 x 9 x 9 x 9 x 9 x 9 x 9 = 9⁷

\(8x8=8^2=64\)

\(9x9x9x9x9x9x9=9^7=4782969\)

\(8.8=8 ^2=64\)

\(9.9.9.9.9.9.9=9^7=4782969\)

9nhân9=81

9x9=81

9.9

=9^2

=81

kik nhá

\(\dfrac{5\times4^{15}\times9^9-4\times3^{20}\times8^9}{5\times2^{10}\times6^{19}-7\times2^{29}\times27^6}\\ =\dfrac{5\times2^{30}\times3^{18}-2^2\times3^{20}\times2^{27}}{5\times2^{10}\times3^{19}\times2^{19}-7\times2^{29}\times3^{18}}\\ =\dfrac{5\times2^{30}\times3^{18}-2^{29}\times3^{20}}{5\times2^{29}\times3^{19}-7\times2^{29}\times3^{18}}\\ =\dfrac{2^{29}\times3^{18}\times\left(5\times2-3^2\right)}{2^{29}\times3^{18}\times\left(5\times3-7\right)}\\ =\dfrac{10-9}{15-7}\\ =\dfrac{1}{8}\)

a) \(\dfrac{5\times6\times12}{6\times12\times7}=\dfrac{5}{7}\)

b) \(\dfrac{9\times8\times15}{15\times9\times16}=\dfrac{1}{2}\)

 = 2^19 x (3^3)^3 + 3 x 5 x (2^2)^9 x (3^2)^4 / 2^9 x 3^9 x 2^10 + (2^2)^10 x 3^10

 = 2^19 x 3^9 + 3^9 x 2^18 x 5 / 2^19 x 3^9+2^20 x 3^10 

 = 3^9 x 2^18 x (2+5) / 3^9 x 2^19 x (1 + 2 x 3)

 = 3^9 x 2^18 x 7 / 3^9 x 2^19 x 7 = 1/2

k mk nha

Cảm ơn bạn đẹp trai 

=31446

đây bài giai nè chưa chăc dung đâu

99+43*9*9*9=

=99+43*9*9*9*1

=9*(99+43+1)

tiếp đó tự làm

99 + 43 * 9 * 9 * 9 = 31446

x+702=405  x=-297                                                                                       

\(x+78\cdot9=9\cdot45\)

\(\Leftrightarrow x+702=405\)

\(\Leftrightarrow x=-297\)

x + 78 x 9 = 9 x 45

x + 78 x 9 = 405

x + 702 = 405

x = 405 - 702

x= -297

\(A=\dfrac{2^{19}\cdot3^9-3\cdot5\cdot2^{18}\cdot3^8}{2^9\cdot2^{10}\cdot3^9+2^{20}\cdot3^{10}}\)

\(=\dfrac{2^{19}\cdot3^9-2^{18}\cdot3^9\cdot5}{2^{19}\cdot3^9+2^{20}\cdot3^{10}}\)

\(=\dfrac{2^{18}\cdot3^9\left(2-5\right)}{2^{19}\cdot3^9\cdot7}=\dfrac{1}{2}\cdot\dfrac{-3}{7}=\dfrac{-3}{14}\)