(4/a+1 + 2a/a^2-1 - 1/a-1)*(a^2+2a+1) выражение

Решим по действиям:
1) 4/(a + 1) + 2a/(a² - 1) = 4/(a + 1) + 2a/(a - 1)(a + 1) = 4(a - 1)/(a + 1)(a - 1) +
+ 2a/(a - 1)(a + 1) = (4a - 4 + 2a)/(a - 1)(a + 1) = (6a - 4)/(a - 1)(a + 1)
2) (6a - 4)/(a - 1)(a + 1) - 1/(a - 1) = (6a - 4)/(a - 1)(a + 1) - (a + 1)/(a - 1)(a + 1) = (6a - 4 - a - 1)/(a - 1)(a + 1) = (5a - 5)/(a - 1)(a + 1) = 5(a - 1)/(a - 1)(a + 1) =
= 5/(a + 1)
3) 5/(a + 1)·(a² + 2a + 1) = 5(a + 1)²/(a + 1) = 5a + 5 
ответ: 5a + 5.