Question

1)$\frac{ a^{3}-a }{ a^{2}+a }$

Answer 1

a· (a² -1) / a · ( a +1) = ( a² - 1) / ( a + 1) = ( a +1) · ( a -1)  / ( a +1 ) =
               = a - 1 

Answer 2

$\displaystyle \frac{a^3-a}{a^2+a} = \frac{a(a^2-1)}{a(a+1)} = \frac{a(a-1)(a+1)}{a(a+1)} =a-1$