1) 2/(x ^ 2 + 5 * x) + 3/(2 * x - 10) = 15/(x ^ 2 - 25);2/(x * (x + 5) + 3/(2 * (x - 5)) = 15/(x ^ 2 - 25);(2 * 2 * (x - 5) + 3 * x * (x + 5))/(2 * x * (x + 5) * (x - 5)) = 15/(x ^ 2 - 25);(4 * (x - 5) + 3 * x * (x + 5)/(2 * x) = 15;4 * x - 20 + 3 * x ^ 2 + 15 * x = 30 * x;3 * x ^ 2 - 11 * x - 20 = 0;D = 121 + 4 * 3 * 20 = 361;x1 = (11 + 19)/6 = 30/6 = 5;x2 = (11 - 19)/6 = - 8/6 = - 4/3;2) 2 * x/(x + 2) + 1/(x - 2) - 4:(x^2 - 4) = 0;2 * x * (x - 2) + 1 * (x + 2) - 4 = 0;2 * x ^ 2 - 4 * x + x + 2 - 4 = 0;2 * x ^ 2 - 3 * x - 2 = 0;D = 9 + 4 * 2 * 2 = 25;x1 = (4 + 5)/6 = 11/6;x2 (4 - 5)/6 = - 1/6;3)((x ^ 2 + 6) / (x - 4 ))^2 = ((5 * x / (4 - x ^ 2)) ^ 2;(x ^ 2 + 6) * (4 - x ^ 2) = 5 * x * (x - 4);4 * x ^ 2 - x ^ 4 + 24 - 6 * x ^ 2 = 5 * x ^ 2 - 20 * x;- x ^ 4 + 24 - 2 * x ^ 2 = 5 * x ^ 2 - 20 * x; - x ^ 4 + 24 - 2 * x ^ 2 - 5 * x ^ 2 + 20 * x = 0;- x ^ 4 - 7 * x ^ 2 + 20 * x + 24 = 0;Отсюда, х = 2,38 и х = 0,89.