Answer:
4.2 × [tex]10^{-1}[/tex]
Step-by-step explanation:
2.1 × [tex]10^{-3}[/tex] × 2 × [tex]10^{2}[/tex]
2.1 + 2 = 4.2
2 - 3 = - 1
2.1x^10+−3x^104