Rewrite the function by completing the square g(x)=x^2+15x+54

Ineed if you could explain and give me the answer you! this needs done

Which function has the domain x> -11

Abicycle training wheel has a radius of 3 inches. the bicycle wheel has a radius of 10 inches.approximately how much smaller, in square inches and rounded to the nearest hundredth, is the area of the training wheel than the area of the regular wheel? *