Question 752760
let the cube has edges x in
so the volume= x^3
2 in is cut from one side 
so the new volume=(x-2)*x^2
as per question
x^3-(X-2)*x^2=75
or x^3-x^3+2x^2=75
or 2x^2=75
or x^2=75/2=37.5
or x=sqrt(37.5)=19.37 in