11th grade math
posted by Channing .
A box without a lid is constructed from a 38 inch by 38 inch piece of cardboard by cutting in. squares from each corner and folding up the sides.
a) Determine the volume of the box as a function of the variable .
b) Use a graphing calculator to approximate the values of that produce a volume of 3858.1875.
c)There are 3 values of that produce the given value but only two of them are acceptable in the context of the problem. List the two answers, to at least one decimal place.
*I don't even know how to start please help!

length of box = 38  2x
width of box = 382x
volume of box = V = (382x)(382x)(x)
V = (1444152x+4x^2)x
V = 1444x 152x^2 +4x^3
that should get you started 
SO would I set both (1444152x+4x^2)x
and 1444x 152x^2 +4x^3 equal to 3858.1875 to find part c? 
6x2  21xy + 8xz  28yz.

had this same probem for college precalculue couldn't solve B any other way but guess and check/logic x=4.5

secondary largest possible answre is
Answer: x⋅(382⋅x)2
Answer: 8.06181572077 
x values sould be 4.75 and 8.06........
so your answers are 4.8 and 8.1