Answer:
both of them thats the answer
Step-by-step explanation:
Answer:
60.5 milligrams per square centimeter First, determine how many half lives have expired by dividing the time by the half-life. So: 55/20 = 2.75 That means that only 2^(-2.75) = 0.148650889 = 14.8650889% of the original substance remains. So just divide the amount remaining by 0.148650889 to get the original amount. 9 / 0.148650889 = 60.5445419 So originally, there was 60.5 milligrams per square centimeter 55 years ago.
Answer:
75.062c
Step-by-step explanation:
To find the missing side use pythagorean theorem
So 
Solve for b, b= 6.021
To find the area use 
bh
So (6.021+19)(6)= area
And you get 75.062
m^2 -11m -60 = 0
m^2 -11m =60
(m^2 -11m + 121/4) = 361/4
(m - 11/2)^2 = 361/4
m - 11/2 = + or - 19/2
m = 11/2 + 19/2, 11/2 - 19/2
m = 15, -4
---------------------------------------------------
m^2 -11m -60
(11 +- Square root (121 +240))/2
11/2 +- 19/2
m= 15, -4
----------------------------------------------------
m^2 -11m -60
(m - 15) (m + 4)
m = 15, -4
