Question 1127661
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The solution by tutor FrankM is probably right in saying that the solution is found more easily with guess-and check than with formal algebra.<br>
But I would do the guess-and-check work differently than what he shows.<br>
Without expanding the expression, the equation for the volume of the box is<br>
x(x+3)(x+7)=480<br>
Since the product is 480, one of the factors must be 5, or perhaps a multiple of 5.<br>
So try x = 5, and it works.<br>
So the dimensions are 5, 8, and 12.