The applicable decay formula is:N = No*e^(-kt)WhereN = Mass left after time tNo = Original massk = constantt = half lifeUsing the values given,N/No = e^(-0.1446t) = 1/2ln (1/2) = -0.1446 t *ln e^1-0.6931 = -0.1446 tt = 0.6331/0.1446 = 4.79 daysTherefore, half-life is 4.8 days.
-5—->-29
-1—->-5
0—->1
1—->7
In the given question Laura has $30 to spend on food for the week.
According to the question we have to set the inequality between total amount and amount spent on food.
Amount spend by Laura on food for the week = $30
Let the amount spent by Laura on food be x
So she has to spend up to $30
So inequality will be 
So option b is the answer
#1
Clear shown in graph
#2
No
At. no where graph passes through origin so y intercept is not 0 at anywhere
#3
Domain is x values
#4
Range is y values set