Answer:
[tex]\large\boxed{-0.04ab^{19}}[/tex]
Step-by-step explanation:
[tex]a(-0.2b^6)^3(5b)\qquad\text{use}\ (ab)^n=a^nb^n\\\\=a(-0.2)^3(b^6)^3(5b)\qquad\text{use}\ (a^n)^m=a^{nm}\\\\=a(-0.008)(b^{18})(5b)\\\\=(-0.008\cdot5)ab^{18}b\qquad\text{use}\ a^na^m=a^{n+m}\\\\=-0.04ab^{19}[/tex]
