Help me answer these function questions please

For f(x)=2x+1 and g(x)= x^2 -7, find (f•g)(x)

It says factor each expression 49x-28?

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.