Basic Highschool Math Circles, need answers quick please and thanks

Solve the system of equations. y= 2x y= x^2 - 15

Graph g(x)=2cosx . use 3.14 for π . use the sine tool to graph the function. graph the function by plotting two points. the first point must be on the midline and closest to the origin. the second point must be a maximum or minimum value on the graph closest to the first point.

On this question. a hypothermia occurs when a person's body temperature drops below 95 degrees fahrenheit. write and solve an inequality that describes how much lower the body temperature of a person with hypothermia will be than the body temperature of a person with a normal temperature of 98.6 degrees fahrenheit