Question

СРОЧНО ДАЮ 50 БАЛОВ!!!!!!!!!!!!

Answer 1

$0,3\cdot 10^8\cdot 1,4\cdot 10^{-4}=0,3\cdot 1,4\cdot 10^8\cdot 10^{-4}=\frac{3\cdot 14}{100}\cdot 10^{8-4}=\frac{42}{100}\cdot 10^4=0,42\cdot 10^4$