(x+1)/(x-5) + (x-1)/(x+5) = (7x+5)/(x^2-25)
Observam ca x^2-25 = (x+5)(x-5).
Pentru a aduce toata ecuatia la acelasi numitor amplificam prima fractie cu (x+5) si a doua fractie cu (x-5)
(x+1)(x+5)/(x^2-25) + (x-1)(x-5)/(x^2-25) = (7x+5)/(x^2-25)
(x+1)(x+5) + (x-1)(x-5) = 7x+5
x^2 + 5x + x + 5 + x^2 - 5x - x + 5 = 7x + 5
2x^2 + 10 - 7x -5 = 0
2x^2 - 7x + 5 = 0
Delta = b^2-4ac = 49-40 = 9
x1,2 =(-b+sau-radical din delta)/2a
x1,2 = (7+sau-3)/4
x1 = 10/4 = 5/2
x2 = 4/4 = 1