Answer:
can u add a picture?
Step-by-step explanation:
-16t^2+400=0
16t^2=400
take square root on both sides.

4t=20
t=20/4
t=5
Answer:
ask ur teacher
Step-by-step explanation:
Scientific notation:
8.41 x 10^7
expanded form:
84100000
Answer:
Option 3 is correct that is