I am stuck on this algebra question please can someone help me?

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

Aline on the wall and a line on the floor are skew. always, sometimes, or never?

If $740 is invested at an interest rate of 11% per year and is compounded continuously, how much will the investment be worth in 7 years? use the continuous compound interest formula a = pert.