Step-by-step explanation:
(n-2)×180=3420
180n-360=3420
180n=3420+360
180n=3780
n=3780/180
n=21
that is, the number of sides is 21
to get the size of each exterior angle=
360/21
=17.14°
37.95/5=7.59$ for each person that will pay for the ballon party
x represents the total sales and y represents the total amount of money that Gary earns.
Gary's monthly salary = 1500
His commission = 10% of his sales
= 
= 0.1x
So, total amount of money Gary earns is y = 0.1x + 1500.
D.
The equation is y = 1, so the only number of the range is 1