#9) if x^a = 3 then x^4a - 5 equals what

#1) The elevation of a hiking trail is modeled by the function h(x) = 2x³ + 3x- 17x + 12 when h is the height measured in metres above sea level and x is the horizontal position from a ranger station, measured in kilometers. If x is negative the position is to the west of the station and if x is positive the position is to the east. At what distances from the ranger station is the trail above sea level ?

#2) An open topped box made of sheet of cardboard measures 50 cm by 30 cm by cutting congruent squares from the four corners and folding up the sides. Write a polynomial function that can present this volume of such a box and determine the dimensions that result in a volume greater than 4000 cm³