Answer:
In 2030 I will have $ 9,875.32 in my account.
Step-by-step explanation:
Given that I invested $ 10,000 in 2020, and it increases 5% for 5 years, but over the next 5 years it decreases in value by 5% each year, to determine how much I will have in 2030 the following calculation must be performed: 
 
10,000 x 1.05 x 1.05 x 1.05 x 1.05 x 1.05 = X 
10,500 x 1.05 x 1.05 x 1.05 x 1.05 = X 
11.025 x 1.05 x 1.05 x 1.05 = X 
11,576.25 x 1.05 x 1.05 = X 
12,155.06 x 1.05 = X 
12,762.81 = X (2025) 
 
12,762.81 x 0.95 x 0.95 x 0.95 x 0.95 x 0.95 = X 
12,124.67 x 0.95 x 0.95 x 0.95 x 0.95 = X 
11,518.44 x 0.95 x 0.95 x 0.95 = X 
10,942.51 x 0.95 x 0.95 = X 
10,395.39 x 0.95 = X 
9,875.32 = X (2030) 
 
Thus, in 2030 I will have $ 9,875.32 in my account.