AN OPEN BOX IS TO BE MADE FROM A CARDBOARD 20 INCHES BY 14 INCHES, BY CUTTING A SQUARE FROM EACH CORNER AND FOLDING UP THE SIDES. FIND THE DIMENSIONS OF THE BOX THAT WILL MAXIMIZE THE VOLUME OF THE BOX

Answer 1

OK! STOP SHOUTING
If an x-inch square is cut from each corner, the volume is
v = (20-2x)(14-2x)*x = 4(x^3 - 17x^2 + 70x
dv/dx = 4(3x^2 - 34x + 70)
So max volume is when x = (17-√79)/3
now you can finish it off