$a){\left(3a\right)}^2=3a\cdot 3a=3^2\cdot a^2$

${\left(0,5x\right)}^3={0,5}^3\cdot x^3$

${\left(-\frac{1}{3}b\right)}^4={\left(-\frac{1}{3}\right)}^4\cdot b^4={\left(-1\right)}^4\cdot {\left(\frac{1}{3}\right)}^4\cdot b^4={\left(\frac{1}{3}\right)}^4\cdot b^4$

${\left(-2\frac{1}{2}x\right)}^2={\left(-2\frac{1}{2}\right)}^2\cdot x^2={\left(-1\right)}^2\cdot {\left(2\frac{1}{2}\right)}^2\cdot x^2={\left(2\frac{1}{2}\right)}^2\cdot x^2$

$b){\left(-2xy\right)}^2={\left(-2\right)}^2\cdot x^2\cdot y^2={\left(-1\right)}^2\cdot 2^2\cdot x^2\cdot y^2=2^2\cdot x^2\cdot y^2$

${\left(-1,3xyz\right)}^4={\left(-1,3\right)}^4\cdot x^4\cdot y^4\cdot z^4={\left(-1\right)}^4\cdot {\left(1,3\right)}^4\cdot x^4\cdot y^4\cdot z^4={\left(1,3\right)}^4\cdot x^4\cdot y^4\cdot z^4$

${\left(-1\frac{1}{2}xyaz\right)}^5={\left(-1\frac{1}{2}\right)}^5\cdot x^5\cdot y^5\cdot a^5\cdot z^5={\left(-1\right)}^5\cdot {\left(1\frac{1}{2}\right)}^5\cdot x^5\cdot y^5\cdot a^5\cdot z^5$