the answer would be D....................................................
Answer:
141.625
Step-by-step explanation:

Answer:
=209.09 mg
Step-by-step explanation:
given: material= radium
half life= 1590 years
initial mass
=500mg
we know that to calculate the amount left we use
= 


therefore
= 
=209.09058407921 mg
=209.09 mg amount left after 2000 years
First 10:38 am
second 1 hr and 9 m
Five less than twice what negative number squared is 157 <- put into an expression
-5 + 2(-x^2) = 157
Now simplify:
-5 + -2x^2 = 157
-2x^2 = 162
-2x^2 - 162 = 0
2x^2 + 162 = 0
x^2 + 81 = 0