Consider the following pseudocode.

$//$ assume that $n$ has a value that is large $($greater than or equal to $4)$

xlarr$0$

for ilarr$4$ to $n$ do

for jlarri to $n$ do

for klarr$1$ to $j$ do

xlarrx$+k\frac{,}{\frac{?}{?}}$larr THIS LINE

a$)$ Write an expression $($probably involving summations$)$ for how many times the indicated line of code is executed as a function of n$.$ Simplify the expression into closed form $($no summation symbols$).$ Show all of your work.

b$)$ Write an expression $($probably involving summations$)$ for the value of the variable x $($as a function of n$)$ after executing the code? Simplify the expression into closed form. Show all of your work. $($Hint: this expression should be different from the one in part a$)$