An equilateral triangular tent has sides that measure x−10x-10 units. its perimeter is 63 units. what is the value of x? enter your answer in the box.

This problem says nothing about the height of the tent, so I must assume that the "equilateral triangle" is the BASE of the tent.

Since the 3 sides of this base are equal, the perimeter is 3(x-10x - 10) units, and this equals the given 63 units.

Thus, 63 = 3x - 30x - 30, or      93 = -27x.  Thus, x = -93/27, or -31/9.

There may be a problem here with the expression you typed in:

x - 10x -10

because x - 10x = -9x, so there is no reason to type in x-10x.

Double check to ensure that you have correctly typed the original problem statement.