- Xin ctlhn
44.
a) $25^3$ : $5^2$
= $5^6$ : $5^2$
= $5^4$
b) $(\frac{3}{7}$)^21 : ($\frac{9}{49}$)^6
= $(\frac{3}{7}$)^21 : $(\frac{3}{7}$)^12
= $(\frac{3}{7}$)^9
c) 3 - (-$\frac{6}{7}$)^0 + ($\frac{1}{2}$)^2 : 2
= 3 + 1 + $\frac{1}{4}$ : 2
= 4 + $\frac{1}{8}$
= $\frac{33}{8}$