Question 586477
x=height (the one no information is given about)

height=x   length=x+8   width=x-2   volume=96

volume=height * length * width

96=x(x+8)(x-2)   substitute in what you know

{{{96=x^3+6x^2-16x}}}  multiply out
{{{0=x^3+6x^2-16x-96}}}  subtract 96
{{{0=x^2(x+6)-16(x+6)}}}  factor by grouping
{{{0=(x^2-16)(x+6)}}}    continue factoring
16=x^2 or x=-6       continue factoring
x=+-4 or x=-6     solve
x=4  because it cannot be negative

height=4  length=12  width=2