Nathan has a sculpture in the shape of a pyramid. The height of the sculpture is 3 centimeters less than the side length, x,of its square base. Nathan uses the formula for the volume of a pyramid to determine the dimesnsioms of the sculpture. V=1/3 a^2h Here, a is the side length of the pyramids square base and h is its height. If 162 cubic centimeters of clay were used to make the sculpture, the equation x^3+_x^2+_=0 can be used to find that the length of the sculptures base is _ centimeters.