Question

Решите уравнение 4/(x-9)+9/(x-4)=2

Answer 1

ОДЗ
x ≠ 9; x ≠ 4

4(x - 4) + 9(x - 9) = 2(x - 4)(x - 9)
4x - 16 + 9x - 81 = 2(x^2 - 13x + 36)
13x - 97 = 2x^2 - 26x + 72
2x^2 - 26x + 72 - 13x + 97 = 0 
2x^2 - 39x + 169 = 0 
D = 169 = 13^2
x1 = ( 39 + 13)/4 = 13
x2 = (39 - 13)/4 = 6,5

Ответ
6,5; 13