Answer:
A.( 3m+28)/4
Step-by-step explanation:
So basically since it is addition we just add 9 to -2 to get 7. So then the equation becomes (3m/4)+7. Then we will multiply 7 by 4 to get common denominator so it will be (3m+(7*4))/4 which is (3m+28)/4.
Area = πr^2
π4^2 =16π
=50.3
7978 years
Step-by-step explanation:
A = A02^(-t/hl)
where hl = half-life.
Dividing both sides by A0 and taking the logarithm, we get
ln(A/A0) = -(t/hl)ln2
or solving for t,
t= -(hl)ln(A/A0)/ln2
note that A/A0 = 0.38
t = -(5715 yrs)[ln(0.38)/ln2]
= 7978 years
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