Need with advanced algebra question. anybody?

lionel deposited $3,631.23 in a savings account that earns 1.9% simple interest. what will lionel's account balance be in 8 months?
a. $4,183.18 b. $3,531.23 c. $3,700.22 d. $3,677.23

To find the extreme values of a function f(x.y) on a curve x-x(t), y y(t), treat f as a function of the single variable t and use the chain rule to find where df/dt is zero. in any other single-variable case, the extreme values of f are then found among the values at the critical points (points where df/dt is zero or fails to exist), and endpoints of the parameter domain. find the absolute maximum and minimum values of the following function on the given curves. use the parametric equations x=2cos t, y 2 sin t functions: curves: i) the semicircle x4,y20 i) the quarter circle x2+y-4, x20, y20 b, g(x,y)=xy

Find the measure of the interior angles of the following regular polygons: a triangle, a quadrilateral, a pentagon, an octagon, a decagon, a 30-gon, a 50-gon, and a 100-gon.

Solve this system of equations. 12x − 18y = 27 4x − 6y = 10