Ở câu a) số mũ lúc nào cug dương mà bạn ( 45^-10 = 45¹⁰). Nếu số mũ là dương thì:

            a)\(\frac{45^{10}.5^{20}}{75^{15}}\)

        = \(\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(3.5^2\right)^{15}}\)

        = \(\frac{3^{20}.5^{10}.5^{20}}{3^{15}.5^{30}}\)

         = \(\frac{3^{20}.5^{30}}{3^{15}.5^{30}}\)

         = \(\frac{3^5.1}{1.1}\)

         = \(\frac{243}{1}\)

         = 243

      b)\(\frac{2^{15}.9^4}{6^6.8^2}\)

          = \(\frac{2^{15}.\left(3^2\right)^4}{\left(2.3\right)^6.\left(2^3\right)^2}\)

          = \(\frac{2^{15}.3^8}{2^6.3^6.2^6}\)

          = \(\frac{2^{15}.3^8}{2^{12}.3^6}\)

          = \(\frac{2^3.3^2}{1.1}\)

          = \(\frac{8.9}{1}\)

          = \(\frac{72}{1}\)

          = 72

cảm ơn bn

\(M=\frac{8^{20}+4^{20}}{4^{25}+64^5}=\frac{1^{20}+1^{20}}{1^{25}+8^5}=\frac{1}{32769}\)

\(N=\frac{6^6+6^3\cdot3^3+3^6}{73}=\frac{53217}{73}=729\)

T khó quá!

=\(\left[\dfrac{\left(0,4.2\right)^5}{\left(0,4\right)^6}+\dfrac{2^9.2^6.3^8}{\left(3.2\right)^6.2^9}\right]=\left[\dfrac{\left(0,4\right)^5.2^5}{\left(0,4\right)^6}+\dfrac{2^6.3^8}{3^6.2^6}\right]\)

=\(\left[\dfrac{2^5}{0,4}+3^2\right]\)

=\(\left[80+9\right]=89\)

\(\left[\dfrac{\left(2.0,4\right)^5}{0,4,0,4^5}+\dfrac{2^{15}.3^8}{3^6.2^6.2^9}\right]\div\dfrac{3^{20}.5^{30}}{3^{15}.5^{30}}\)

\(=\left[\dfrac{2^5.0.4^5}{0,4.0,4^5}+\dfrac{2^{15}.3^8}{3^6.2^{15}}\right]\div3^5\)

\(=\left[\dfrac{2^5}{0,4}+3^2\right]\div243\)

\(=80+\left(3^5\div3^2\right)\)

\(=80+3^3\)

\(=80+27\)

\(=107\)

c. 2¹⁵. 9⁴/ 6⁶. 8³ = 2¹⁵. (3²)⁴/( 2.3 )⁶. (2³)³

                         = 2¹⁵. 3⁸/ 2⁶.3⁶.2⁹

                         = 3²=9

a) (0.8)^5:(0,4)^6

   =(0,4)^10:(0,4)^6

   = (0,4)^4

b)  (0,125)^3*512

   = 1

c)45^10*5^20/75^15

=243

d) 2^15*9^4/6^6*8^3

=2359296

nhận đúng cho mk nha