Tính 120^3/40^3

Giải:

a) \(\dfrac{120^3}{40^3}=\left(\dfrac{120}{40}\right)^3=30^3=2700\)

b) \(\dfrac{390^4}{130^4}=\left(\dfrac{390}{130}\right)^4=30^4=810000\)

c) \(\dfrac{3^2}{\left(0,375\right)^2}=\left(\dfrac{3}{0,375}\right)^2=8^2=64\)

Đáp số: a) 2700; b) 810000; c) 64.

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Bài 50. Tính :

a)\(\left(\dfrac{1}{5}\right)^5.5^5\);

b)\(\left(0,125\right)^3.512\);

c)\(\left(0,25\right)^4.1024\).

a) \(\left(\dfrac{1}{5}\right)^5.5^5\)

\(=\dfrac{1}{3125}.3125\)

= 1

b) \(\left(0,125\right)^3.512\)

\(=\dfrac{1}{512}.512\)

= 1

c) \(\left(0,25\right)^4.1024\)

= \(\dfrac{1}{256}.1024\)

= 4

Tính:

a, \(\left(2^2\right)^{\left(2^2\right)}\)

b, \(\dfrac{\left(\dfrac{-5}{7}\right)^{n+1} }{\left(\dfrac{-5}{7}\right)^n}\left(n\ge1\right)\)

c, \(\dfrac{8^{14}}{4^{12}}\)

a/ \(\left(2^2\right)^{\left(2^2\right)}=4^4=256\)

b/ \(\dfrac{\left(-\dfrac{5}{7}\right)^{n+1}}{\left(-\dfrac{5}{7}\right)^n}=\dfrac{\left(-\dfrac{5}{7}\right)^n.\left(-\dfrac{5}{7}\right)}{\left(-\dfrac{5}{7}\right)^n}=-\dfrac{5}{7}\)

c/ \(\dfrac{8^{14}}{4^{12}}=\dfrac{\left(2^3\right)^{14}}{\left(2^2\right)^{12}}=\dfrac{2^{42}}{2^{24}}=2^{18}\)