Provide an asymptotic runtime complexity of each recurrence using Big O Notation. For these recurrences, do not directly use the Master Theorem to find the asymptotic time complexity $($i$.$e$.$ do not plug in values of $a,b,d$ directly into the Master Theorem to find the Big $O$ time complexity$).$ Make sure to show your work in order to justify your answer!

$($a$)T(n)=8T(\frac{n}{2})+n$

$($b$)T(n)=2T(\frac{n}{4})+T(\frac{n}{2})+n$

$($c$)$