tìm giá trị của biểu thức sau

a) 45 mũ 10 . 5 mũ 20 / 75 mũ 15

b) (0,8) mũ 5 / (0,4) mũ 6

c) 2 mũ 15 . 9 mũ 4 / 6 mũ 6 . 8 mũ 3

bài làm là:

a) 45^10.5^20/75 ^ 15

=(5.9)^10.5^20/(5.15)^15

=5^10.9^10.5^20/5^15.15^15

=5^30.3^20/5^15.3^15.5^15

=5^30.3^20/5^30.3^15

=5^30.3^20/5^30.3^15

=3^5

=243

mấy ý kia mình chia tính được ....A,hihi

\(\frac{45^{10}.5^{20}}{75^{15}}=\frac{\left(3^2.5\right)^{10}.5^{20}}{\left(3.5^2\right)^{15}}=\frac{\left(3^2\right)^{10}.5^{10}.5^{20}}{3^{15}.\left(5^2\right)^{15}}=\frac{3^{20}.5^{30}}{3^{15}.5^{30}}=3^5=243\)

\(a,=-2\sqrt{5}+9\sqrt{5}-24\sqrt{5}-\sqrt{5}=-18\sqrt{5}\)

\(b,=2\sqrt{3}-5\sqrt{3}+4\sqrt{3}-7\sqrt{3}=-6\sqrt{3}\)

\(c,=3\sqrt{3}+7\sqrt{3}-9\sqrt{3}+11\sqrt{3}=12\sqrt{3}\)

a) Ta có: \(-\sqrt{20}+3\sqrt{45}-6\sqrt{80}-\dfrac{1}{5}\sqrt{125}\)

\(=-2\sqrt{5}+9\sqrt{5}-24\sqrt{5}-\dfrac{1}{5}\cdot5\sqrt{5}\)

\(=-17\sqrt{5}-\sqrt{5}=-18\sqrt{5}\)

b) Ta có: \(2\sqrt{3}-\sqrt{75}+2\sqrt{12}-\sqrt{147}\)

\(=2\sqrt{3}-5\sqrt{3}+4\sqrt{3}-7\sqrt{3}\)

\(=-6\sqrt{3}\)

A= (9¹⁰.5¹⁰​.5¹⁰​)/(25¹⁰​.3^​10)=(3^​20​.5²⁰​)/(5^​20.3^​10)=3^​10

​B=(0,8)^​5/(0,4)⁶= (2.0,4)⁵​/0,4.0,4⁵ ​= 2⁵.0,4⁵/0,4.0,4⁵ = 2^​5​/0,4 = 80

​C= 2¹⁵.9⁴​/6^​6.8³= 2_​^​15​.3⁸​/3⁶.2⁶.2⁹=2^​15.3⁸/3⁶.2^​15=3²=9

bo deo quantam

45^10 x 5^20 / 75^15

= ( 3^2 x 5)^10 x 5^20 / ( 3 x 5^2)^15

= 3^20 x 5^10 x 5^20 / 3^15 x 5^30

= 3^5

= 243

p/s : theo mk thì lm như vậy đó

1/3^15

\(\frac{36}{10}=\frac{36:2}{10:2}=\frac{18}{5}\)

\(\frac{75}{36}=\frac{75:3}{36:3}=\frac{25}{12}\)

\(\frac{75}{300}=\frac{75:75}{300:75}=\frac{1}{4}\)

\(\frac{4}{100}=\frac{4:4}{100:4}=\frac{1}{25}\)

36/10=18/5

75/36=25/12

75/300=1/4

4/100=1/25

1) \(\dfrac{5}{10}=\dfrac{5:5}{10:5}=\dfrac{1}{2}\)

\(\dfrac{-18}{-27}=\dfrac{-18:\left(-9\right)}{-27:\left(-9\right)}=\dfrac{2}{3}\)

\(\dfrac{-42}{105}=\dfrac{-42:21}{105:21}=\dfrac{-2}{5}\)

\(\dfrac{75}{-135}=\dfrac{75:\left(-15\right)}{-135:\left(-15\right)}=\dfrac{-5}{9}\)

\(\dfrac5{10}=\dfrac{5.1}{5.2}=\dfrac12\\\dfrac{-18}{-27}=\dfrac{(-9).2}{(-9).3}=\dfrac23\\\dfrac{-42}{105}=\dfrac{21.(-2)}{21.5}=\dfrac{-2}5\\\dfrac{75}{-135}=\dfrac{(-15).(-5)}{(-15).9}=\dfrac{-5}9\)

11/12=1/2 , 36/10=18/5 , 75/36 = 25/12 , 14/28 = 1/2 , 48/30 = 8/5

1/2;18/5;25/12;1/2;24/15