I believe it's 7.5 but I could be wrong.
did u ever get the answers
Answer:

So then the integral converges and the area below the curve and the x axis would be 5.
Step-by-step explanation:
In order to calculate the area between the function and the x axis we need to solve the following integral:

For this case we can use the following substitution
and we have 

And if we solve the integral we got:

And we can rewrite the expression again in terms of x and we got:

And we can solve this using the fundamental theorem of calculus like this:

So then the integral converges and the area below the curve and the x axis would be 5.
Interest = (Principal X rate X time)/100
Interest =421*9*4/100
Interest = 151.56 dollars
I cant see it well try to get a better pic and i can help you