[tex]\bf a)\ \ [-2\cdot(-9)]^2=18^2=324 \\ \\\[ [-2\cdot(-9)]^2=(-2)^2\cdot(-9)^2=4\cdot81=324\\ \\ \\ b)\ \ \[[(-2)\cdot(-3)\cdot(+5)]^1=(-2)^1\cdot(-3)^1\cdot(+5)^1=-2\cdopt(-3)\cdot5=6\cdot5=30\\ \\ \[[(-2)\cdot(-3)\cdot(+5)]^1=(6\cdot5)^1=30^1=30[/tex]