What number should go in the circle to make the operation correct?? Answer with complete working!

(if f(x)=4x^2 and g(x)=x+1, find (f o g)(x)

Find the solution of system of equation y= x-4 y=4x+2

Danielle earns a 7.25% commission on everything she sells at the electronics store where she works. she also earns a base salary of $750 per week. what were her sales last week if her total earnings for the week were $1,076.25?