Question

Tính:

a) 25³ : 5²

b) \(\left(\frac{3}{7}\right)^{21}\) : \(\left(\frac{9}{49}\right)^6\)

c) 3- \(\left(\frac{-6}{7}\right)^0\) + \(\left(\frac{1}{2}\right)^2\) : 2

 

Answer 1

\(a.25^3:5^2=\left(5^2\right)^3:5^2=5^6:5^2=5^{6-2}=5^4=625\)

\(b.\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{49}\right)^6=\frac{3}{7}^{21}:\left(\frac{3}{7}^2\right)^6=\frac{3}{7}^{21-12}=\frac{3}{7}^9\)

\(c.3-\left(\frac{-6}{7}\right)^0+\left(\frac{1}{2}\right)^2:2=3-1+\frac{1}{4}.\frac{1}{2}=2+\frac{1}{8}=\frac{17}{8}\)

Answer 2

\(25^3:5^2=5^{15}:5^2=5^{13}\)

\(\left(\frac{3}{7}\right)^{21}:\left(\frac{9}{49}\right)^6=\left(\frac{3}{7}\right)^{21}:\left(\frac{3}{7}\right)^{12}=\left(\frac{3}{7}\right)^9\)