I learned how to find the area of a triangle with 2 numbers (0.5*b*h), but how do you find the area with 4 numbers?

Geometry answer picture question pls . reason and statements

Asap 25 pts + brainlest to right/best answer

Imogene invested $8,000 in a bank account that pays 8 percent simple interest at the end of each year. her friend invested the same amount in stocks where the growth of the investment is represented as 2,000 times the square root of 2 less than the time lapsed in years. if y1 and y2 represent the amount earned in dollars and t is the time lapsed in years, which system of equations correctly represents the situation?