Question

5 punctul b
Dau coroana
Imi trebuie urgent!

Answer 1

Răspuns:

Explicație pas cu pas:

2a/(a + 1)  - 2/(a^2-1) + a/(a - 1) = 2a/(a + 1)  -2/(a +1)(a-1) + a/(a-1) =

[2a(a - 1) - 2 + a (a + 1)]/(a - 1)(a + 1) = (2a^2 - 2a - 2 + a^2 + a) / (a - 1)(a + 1) =

= (3a^2 - a - 2) / (a + 1)(a - 1)

3a*2 - a - 2 = a^2 - a + 2a^2 - 2 = a(a - 1) + 2(a^2 - 1) = a(a - 1) + 2(a - 1)(a + 1) =

= (a - 1) (a + 2a + 2) = (a - 1)(3a + 2)

(a - 1)(3a + 2) / (a + 1)(a - 1) = (3a + 2) / (a + 1)

(9a^2 - 4) / (9a^2 - 6a) = (3a - 2)(3a + 2) / 3a(3a - 2) = (3a + 2)/ 3a

(3a + 2) / (a + 1) : (3a + 2)/ 3a =  (3a + 2) / (a + 1) * 3a/(3a + 2) = 3a/(a + 1)