viết các số sau đướiạng lũy thừa a^n. a,2.4.16.32.2^4 b,75^20=45^10.5^30 24/09/2021 Bởi Nevaeh viết các số sau đướiạng lũy thừa a^n. a,2.4.16.32.2^4 b,75^20=45^10.5^30
a) Ta có $2.4.16.32.2^4 = 2.2^2 . 2^4 . 2^5 . 2^4 = 2^{1+2+4+5+4} = 2^{16}$ b) Ta có $75^{20} – 45^{10}.5^{30} = (25.3)^{20} – (5.9)^{10} .5^{30}$ $= 25^{20} . 3^{20} – 5^{10}.9^{10}.5^{30}$ $=25^{20}.3^{2.10} – 9^{10}.5^{40}$ $=25^{20} . (3^2)^{10} – 9^{10} . 5^{2.20}$ $= 25^{20} . 9^{10} – 9^{10} . (5^2)^{20}$ $= 25^{20} . 9^{10} – 9^{10} . 25^{20} = 0$ Bình luận
a) Ta có
$2.4.16.32.2^4 = 2.2^2 . 2^4 . 2^5 . 2^4 = 2^{1+2+4+5+4} = 2^{16}$
b) Ta có
$75^{20} – 45^{10}.5^{30} = (25.3)^{20} – (5.9)^{10} .5^{30}$
$= 25^{20} . 3^{20} – 5^{10}.9^{10}.5^{30}$
$=25^{20}.3^{2.10} – 9^{10}.5^{40}$
$=25^{20} . (3^2)^{10} – 9^{10} . 5^{2.20}$
$= 25^{20} . 9^{10} – 9^{10} . (5^2)^{20}$
$= 25^{20} . 9^{10} – 9^{10} . 25^{20} = 0$