Question 755281
6x^2+84x+294  (surface area of cube)
.
Since there are 6 sides to a cube, each side must have an area of:
(6x^2+84x+294)6
x^2+14x+49  (area of each side)
factoring:
(x+7)(x+7)
(x+7)^2   
.
therefore:
x+7 (length of each side)