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 dimensions of the sculpture:Here, a is the side length of the pyramid’s square base and h is its height.If 162 cubic centimeters of clay were used to make the sculpture, the equation x3 + x2 + = 0 can be used to find that the length of the sculpture’s base is centimeters.

Let
x-----------> the side length of a pyramid square base
h-----------> the height of the sculpture in the shape of a pyramid

we know that
h=(x-3)
Volume=162 cm³
Volume=x² *(x-3)/3
then
x² *(x-3)/3=162----------> x³-3x²=486----------> x³-3x²-486=0
x³-3x²-486=0-------- this equation can be used to find the length of the sculpture’s base 

using a graph tool-----------> to find the solution
x=9 cm -------------> see the attached figure
h=(x-3)-----> h=9-3--------> h=6 cm

the answer is
the length of the sculpture’s base is 9 cm
the height of the sculpture is 6 cm