Найдем х.

(x - 1)^2 = (14 - x)^2;

x^2 - 2 * x + 1 = 196 - 28 * x + x^2;

-2 * x + 1 = -28 * x + 196;

-2 * x + 28 * x = 196 - 1;

26 * x = 195;

x = 195/26;

x = 7.5.