Let's use "a" to represent the length of the equal sides of the isosceles triangle, and let's use "b" to represent the length of the third side. We're told that one of the equal sides is 2x + 1ft long, so we can set up an equation:
2a + b = 55
We're also told that the other two sides are both 3x - 14ft long, so we can set up another equation:
a = 3x - 14
Now, we can substitute the second equation into the first equation and solve for "b":
2a + b = 55
2(3x-14) + b = 55
6x - 28 + b = 55
b = 83 - 6x
Now, we can substitute both equations into the equation a = 3x - 14 and solve for "x":
3x - 14 = 2x + 1 + 3x - 14
6x - 27 = 0
x = 4.5
Finally, we can substitute "x" into our equations to find the lengths of the sides:
a = 3x - 14 = 3(4.5) - 14 = 0.5
b = 83 - 6x = 83 - 6(4.5) = 55
So the length of the equal sides is 0.5ft, and the length of the third side is 55ft. Therefore, the lengths of the sides of the isosceles triangle are 0.5ft, 0.5ft, and 55ft.