Sam decides to buy 100 shares of abc company. they cost $26.25 a share. the commission is 5% of the total price. what is sam's total cost?

One share cost: $26.25.
Sam wants to buy 100, which means that the total price of the shares is:
100*$26.25=$2625.
There is also commission of 5% of the total amount:
5% of $2625, which is:
(5/100)*$2625=0.05*$2625=$131.25
So, Sam's total cost will be: the total price of the shares + the commission
$2625+$131.25=$2756.25

We will use the property :

sum of interior angles on same side of transversal =180

(8x-14) + (2x+54)=180

10x+40=180

10x=140

x=14