Ireally need badly with calculus question, and ill give you lots of points

Suppose there is a simple index of three stocks, stock abc, stock xyz, and stock qrs. stock abc opens on day 1 with 4000 shares at $3.15 per share. stock xyz opens on day 1 with 5000 shares at $4.30 per share. stock qrs opens on day 1 with 6000 shares at $4.60 per share. the price of stock abc on day 8 begins at $3.50. the price of stock xyz on day 8 begins at $3.90. stock qrs opens on day 8 with a price of $4.50 per share. assume that each stock has the same number of shares that it opened with on day 1. what is the rate of change of this simple index over 1 week?

In the 30-60-90 triangle below side s has a length of and side r has a length

Solve by any method (graphing, substitution or linear combination)y = x - 82x + 3y = 1a) (2, -6)b) (5, -3)c) (4, -4)d) (0, -8)i figured it out. the answer is (5, -3)