$(3$ points$)$

Assume $n$ is a positive integer. Count the number of operations in the loop below:

$x$:$=4$

$y$:$=1$

$z$:$=15$

for $j$:$=7to5n$

$x$:$=2*(x+j)-7$

$y$:$=x+j^2-n+4*j$

$z$:$=n*x+j*y$

next $j$

There are

operations performed in each run of the loop and the loop runs

times, so the total number of operations performed in this loop is