He I need so advice or something GIRLS ONLY!

Alake near the arctic circle is covered by a sheet of ice during the cold winter months. when spring arrives, the ice starts to melt. s(t) models the ice sheet's thickness (in meters) as a function of time tt (in weeks). s(t)=-0.25t+4

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

Need 50 will mark brainliest answer. find the lengths of all the sides and the measures of the angles.