a)=-720

b)=616

c)=10000

d)=-60000

a) 12 . ( - 5 ) . ( - 2 ) . ( - 6 )

= - 60 . 12

= - 720

b) ( - 4 ) . 7 . 11 . ( - 2 )

= - 28 . ( - 22 )

= 616

c) 25 . ( - 5 ) . 4 ( - 20 )

= - 125 . ( - 80 )

= 10 000

d) 125 . ( - 3 ) . ( - 8 ) . ( - 10 )

= - 375 . 80

= - 30 000

Bài 1:

a; (\(\dfrac{1}{4}\)\(x\) - \(\dfrac{1}{8}\)) x \(\dfrac{3}{4}\) = \(\dfrac{1}{4}\)

     \(\dfrac{1}{4}x\) - \(\dfrac{1}{8}\) = \(\dfrac{1}{4}\) : \(\dfrac{3}{4}\)

      \(\dfrac{1}{4}\)\(x\) - \(\dfrac{1}{8}\) = \(\dfrac{1}{4}\) x \(\dfrac{4}{3}\)

    \(\dfrac{1}{4}x\) - \(\dfrac{1}{8}\) =  \(\dfrac{1}{3}\)

      \(\dfrac{1}{4}x\) = \(\dfrac{1}{3}\) + \(\dfrac{1}{8}\)

       \(\dfrac{1}{4}\) \(x\)=  \(\dfrac{8}{24}\) + \(\dfrac{11}{24}\)

          \(\dfrac{1}{4}x=\dfrac{11}{24}\)

           \(x=\dfrac{11}{24}:\dfrac{1}{4}\)

           \(x=\dfrac{11}{24}\times4\)

           \(x=\dfrac{11}{6}\) 

b; \(\dfrac{12}{5}:x\) = \(\dfrac{14}{3}\) x \(\dfrac{4}{7}\)

     \(\dfrac{12}{5}\) : \(x\) = \(\dfrac{8}{3}\)

            \(x\) = \(\dfrac{12}{5}\) : \(\dfrac{8}{3}\)

            \(x\) = \(\dfrac{12}{5}\) x \(\dfrac{3}{8}\)

             \(x\) = \(\dfrac{9}{10}\)

c; \(x+\dfrac{2}{3}\) = 8:4 - 1

   \(x+\dfrac{2}{3}\) = 2 - 1

   \(x+\dfrac{2}{3}\) = 1

  \(x=1-\dfrac{2}{3}\)

  \(x\) = \(\dfrac{1}{3}\)

\(M=\frac{8^{20}+4^{20}}{4^{25}+64^5}\)

\(M=\frac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}\)

\(M=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}\)

\(M=\frac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}\)

\(M=2^{10}\)

\(M=1024\)

a ) 5 ^30 : ( 5^25 . 6 + 5^25 . 9 ) 

 = 5^30 : [ 5^25 ( 6 + 9 ) ]

 = 5^30 : [ 5^25 . 15 ]

 = 5^30 : [ 5^25 . 5 . 3 ]

 = 5^30 : [ 5^26 . 3 ]

 = 5^30 : 5^26 : 3

  = 5^4 : 3

b ) ( 20 . 2^4 + 12 . 2^4 - 48 . 2^2 ) : 8^2

   = ( 20 . 2^4 + 12.2^4 - 12 . 2^2 . 2^2 ) : 8^2

   = ( 20 . 2^4 + 12.2^4 - 12.2^4 ) : 8^2

   = 20 . 2^4 : 8^2

   = 5 . 2^2 . 2^4 : ( 2^3 )^2

   = 5 . 2^6 : 2^6

   = 5

  = 625 : 3

  = 625/3

Lần sau viết đề dễ nhìn chút nhé!Nhìn là thấy không muốn làm rồi.

a) \(5^{30}:\left(5^{25}.6+5^{25}.9\right)\Leftrightarrow5^{30}:\left[5^{25}.\left\{6+9\right\}\right]\)

\(\Leftrightarrow5^{30}:\left[5^{25}.15\right]\)

Bỏ ngoặc đi ta lại có: \(5^{30}:5^{25}.15\)

Theo quy tắt khi phép tính không có ngoặc thì ta làm từ trái sang phải. Ta có:

\(\left(5^{30}:5^{25}\right).15\Leftrightarrow5^{30-25}.15\Leftrightarrow5^5.15\)

\(\Leftrightarrow3125.15=46875\)

b) \(\left(20.2^4+12.2^4-48.2^2\right):8^2\)

\(\Leftrightarrow\left\{\left[2^4.\left(20+12\right)-48.2^2\right]:8^2\right\}\)

\(\Leftrightarrow\left\{\left[2^4.32-48.2^2\right]:8^2\right\}\)

\(\Leftrightarrow\left\{\left[16.32-48.4\right]:64\right\}\)

\(\Leftrightarrow\left\{\left[512-192\right]:64\right\}\Leftrightarrow320:64=5\)

\(\frac{8^{20}+4^{20}}{4^{25}+64^5}=\frac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}=\frac{2^{40}\times\left(2^{20}+1\right)}{2^{30}\times\left(2^{20}+1\right)}=2^{10}=1024\)

Chúc bạn học tốt ^^

Câu 1:

\(\frac{5^4.18^4}{125.9^5.16}\) = \(\frac{5^4.\left(2.9\right)^4}{5^3.9^5.2^4}\) = \(\frac{5^4.2^4.9^4}{5^3.9^5.2^4}\) = \(\frac{5}{9}\)

Câu 2:

\(\frac{\left(-5\right)^{32}.20^{43}}{\left(-8\right)^{29}.125^{25}}\) = \(\frac{5^{32}.\left(4.5\right)^{43}}{\left(-2.4\right)^{29}.\left(5^3\right)^{25}}\) = \(\frac{5^{32}.4^{43}.5^{43}}{\left(-2\right)^{29}.4^{29}.5^{75}}\) = \(\frac{4^{14}.5^{43}}{\left(-2\right)^{29}.5^{43}}\)

=\(\frac{4^{14}}{\left(-2\right)^{29}}\) = = \(\frac{\left[-2.\left(-2\right)\right]^{14}}{\left(-2\right)^{29}}\) = \(\frac{\left(-2\right)^{14}.\left(-2\right)^{14}}{\left(-2\right)^{29}}\) = \(\frac{\left(-2\right)^{14}}{\left(-2\right)^{15}}\) = \(\frac{-1}{2}\)

_ Giúp với mình đang cần gấp ạ

\(\dfrac{4^5.9^4-2.6^9}{2^{10}.3^8+6^8.20}:\sqrt{\dfrac{25}{9}}=\dfrac{2^{10}.3^8-2.2^9.3^9}{2^{10}.3^8+2^8.3^8.2^2.5}:\dfrac{5}{3}\)

\(=\dfrac{2^{10}.3^8-2^{10}.3^9}{2^{10}.3^8+2^{10}.3^8.5}.\dfrac{5}{3}=\dfrac{2^{10}.3^8\left(1-3\right)}{2^{10}.3^8\left(1-5\right)}.\dfrac{5}{3}=\dfrac{1-3}{1-5}.\dfrac{5}{3}=\dfrac{1}{2}.\dfrac{5}{3}=\dfrac{5}{6}\)

\(\dfrac{4^5\cdot9^4-2\cdot6^9}{2^{10}\cdot3^8+6^8\cdot20}\div\sqrt{\dfrac{25}{9}}\)

\(=\dfrac{2^{10}\cdot3^8-2\cdot2^9\cdot3^9}{2^{10}\cdot3^8+2^8\cdot3^8\cdot2^2\cdot5}\div\dfrac{5}{4}\)

=\(\dfrac{2^{10}\cdot3^8\left(1-2\cdot3\right)}{2^{10}\cdot3^8\left(1+5\right)}\div\dfrac{5}{4}\)

=\(\dfrac{1-6}{1+5}\cdot\dfrac{4}{5}\)

=\(-\dfrac{5}{6}\cdot\dfrac{4}{5}\)

=\(-\dfrac{2}{3}\)

\(M=\frac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}=\frac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}=2^{10}\)

\(M=\frac{8^{20}+4^{20}}{4^{25}+64^5}\)

     = \(\frac{\left(2^3\right)^{20}+\left(2^2\right)^{20}}{\left(2^2\right)^{25}+\left(2^6\right)^5}=\frac{2^{60}+2^{40}}{2^{50}+2^{30}}=\frac{2^{40}\left(2^{20}+1\right)}{2^{30}\left(2^{20}+1\right)}=2^{10}\)