Since a standard ticket cost \30$,apremiumticketcost$\$48$. Let $s$ be the number of standard tickets and $p$ be the number of premium tickets. Then

and

Substitute $s=120-p$ into the revenue equation:

Simplify:

So, $48$ premium tickets were sold.

Substitute $x=2$ into the first equation to find $b$:

So $b=-1$. Now use the second equation with $x=2$ and $y=-1$:

Therefore,

From the first equation, $y=3x+4$. Substitute that entire expression for $y$ into the second equation $2x-y=5$:

The parentheses are necessary because the entire expression $3x+4$ is replacing $y$. So the equivalent equation in $x$ is $2x-(3x+4)=5$.

At the intersection, both equations are true for the same point. Rewrite $x+y=9$ as $y=9-x$. Then set the two expressions for $y$ equal:

Add $x$ to both sides and add $3$ to both sides:

So $x=4$. Substitute into either equation:

Therefore, the $y$-coordinate of point $P$ is $5$.

Let $n$ be the number of notebooks and $p$ be the number of pens. The total number of items gives $n+p=18$. The total money gives $3n+2p=43$. Substitute $p=18-n$ into the second equation:

So the club sold $7$ notebooks.