As x increases beyond 6 , which function will have the largest value ? I need help fast please

1) f(x)= 3x^3

2) g(x)= 3x+3

3) h (x)= 3x^2

4) k(x)= 3^x

The area of a rectangle is 10 cm^2. one side of the rectangle is x cm. express the perimeter of the rectangle in terms of x and show that this rectangle cannot have a perimeter of 12 cm. the perimeter of the rectangle in terms of x is __ cm