You could write a set of equations or use the interest formula, A(t)=P(1+r/n)^nt
where p equals the principal amount, r equals the rate/ percentage of interest, n equals the compounding periods and t equals time
Part A:
Given the function

, the absolute maximum or minimum occurs when

.

Using the second derivative test,

Since the second derivative gives a negative number, the given function has a maximum point at

.
And the maximum point is given by:

i.e.

Part B:
Given the function

, the absolute maximum or minimum occurs when

.

Using the second derivative test,

Since the second derivative gives a negative number, the given function has a maximum point at

.
And the maximum point is given by:

i.e. (0.693, 0.25)
Answer:
x = (-5 ± 2√10) / 3
Step-by-step explanation:
5 − 10x − 3x² = 0
Write in standard form:
-3x² − 10x + 5 = 0
Solve with quadratic formula:
x = [ -b ± √(b² − 4ac) ] / 2a
x = [ -(-10) ± √((-10)² − 4(-3)(5)) ] / 2(-3)
x = [ 10 ± √(100 + 60) ] / -6
x = (10 ± 4√10) / -6
x = (-5 ± 2√10) / 3