Answer:
Step-by-step explanation:
1/7+1/13=1/t
multiply both sides by 7*13*t
13t+7t=7*13
21t=91
t=91/19
it will take 4 hours and 8 minutes
Step-by-step explanation:
Exponential function is given by general form 
Where a and b are constants.
say a=1 and b=2 then we can write function as :

or 
To graph this or any exponential function, we just need to find some points then join them by a curved line.
Like plug x=0, 1, 2,... into above function and find points:
plug x=1

Hence point is (1,2)
Find more points similarly then graph them to get the graph as shown below:
Not a sufficient enough question, pls elaborate.
A 12,940 because he hasn't gone back to the top yet
Answer:
Coefficients are -12 and 13