Question 1186811
c, the edge length of the cube
Rectangular Tank Length, c+1
Tank width, c-1
Tank height, c+2
Cube's volume, c^3


Volume of tank is 14 CUBIC ft. less than twice that of the cube.
{{{2c^3-14=(c+1)(c-1)(c+2)}}}
Simplify and solve this for c, first.

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{{{2c^3-14=(c^2-1)(c+2)}}}
{{{2c^3-14=c^3-c+2c^2-2}}}
{{{c^3-2c^2+c-12=0}}}
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{{{c^3-2c^2+c=12}}}
{{{c(c^2-2c+1)=12}}}
{{{highlight_green(c(c-1)^2=12)}}}


Basic multiplication facts may be enough to find c.


If c is 3, then
{{{3(3-1)(3-1)}}}
{{{3*2*2}}}
{{{12}}}-----------same as the right-hand side of the simplified equation.


c, edge length of the cube is  3.