Sagot :
[tex]70 000=7\cdot10^4\\ \\840000000=8,4\cdot10^8\\ \\0,004=4\cdot10^{-3}\\ \\0,000000123=1,23\cdot10^{-7}[/tex]
I believe it's n=-4? It's a negative because the decimal moves to the right 4 times to get 70,000