a cube has a surface area of 6x^2+120x+600 find the length of a side

Question

turingtest · Answer

I assume x represents the length of one side.
The surface area of a cube = 6x^2 where x is the length of one side, because it has 6 faces, each with area x^2, so
6x^2=6x^2+120x+600
120x+600=0
x=-5
hmmm... I guess I would ignore the - sign and just say 5 but something seems wrong here.

turingtest · Answer

what does the x represent if not one side of the cube?

anonymous · Answer

you will have to find x for it i think so 
try this
6x^2+120x+600=0
take 6 common
x^2+20x+100=0
x^2+10x+10x+100=0
x(x+10)+10(x+10)=0
x=-10
length never negative so
lenght 10

turingtest · Answer

why do you think you can set this equal to zero ali?

jhonyy9 · Answer

x2 +20x+100 =0
x_1,_2=(-20 +/- sqrt(400-400))/2 =(-20+/- 0)/2= -10
- so lenght =10