Please help me with these questions

What is the slope of a line that is perpendicular to y = 3x + 1

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?

You buy a veido game for $60 and the sales tax is 8% what is the total cost for the game including the sales tax