SOLUTION: please help me solve this equation: a rectangular piece of cardboard, whose area is 304 square cm, is made into an open box by cutting 2cm square from each corner and turning up

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Question 973550: please help me solve this equation:
a rectangular piece of cardboard, whose area is 304 square cm, is made into an open box by cutting 2cm square from each corner and turning up the sides. if the box is to have a volume of 360 cubic cm, what size cardboard should you start with?
i have gotten all the way to (x^3)+1440-304x=0 and i have no clue what to do form here on out.
Thank you in advance

Answer by josgarithmetic(39617) About Me  (Show Source):
You can put this solution on YOUR website!
You said not how you assigned x, but you may have dimensions x and y for the rectangular cardboard.

Make a drawing and assign some variables, and label the drawing based on these:

A = 304, the area of the cardboard before cutting and folding
d = 2, the side length of the square to remove from each corner
v = 360, the volume of the finished box

FORMULATE EQUATIONS

xy=A ----------- to account for original rectangle area
%28x-2d%29%28y-2d%29d=v ---------- accounting for finished box volume

Those are two equations in two unknown variables. You already have KNOWN values for A, d, and v. You will be able to form a quadratic equation in either x or y, and solve for the variable. Again, notice I say, "QUADRATIC"; and not cubic. Try to work completely in symbols for as far as you can; before finally substituting the given values to evaluate x and y.

First step should be like, y=A/x, and substitute this into the v equation, and simplify... that is really more than "first step".