Answer:
[tex]4.2*10^{-1}[/tex]
Step-by-step explanation:
We want to simplify:
[tex]2.1*10^{-3}\times 2*10^2[/tex]
We rewrite to get:
[tex]2.1*2*10^2*10^{-3}\times10^2[/tex]
We now apply the laws of indices
[tex]4.2*10^{-3+2}[/tex]
We simplify to get [tex]4.2*10^{-1}[/tex]
We leave our final answer is scientific form.
The final answer is therefore:
[tex]4.2*10^{-1}[/tex]