I guess that's f(x) = -3x^2+2
Well :
-3x^2+2=0
-3x^2=-2 / : (-3)
x^2= -2/-3
x^2= 2/3 / sqrt
x= +/ - sqrt(2)/sqrt(3)
We got the zero points.
x ~ +/- 0.81
f(0)= -3(0)^2 + 2
f(0)= 2
Mark three points:
(0.81;0)
(-0.81;0)
(0;2)
Connect with parabolic line and ya got a your graph
There are 13 angles.
We know that

and

(11 angles)
1.

(9 angles)
2.

(8 angles)
3.

(7 angles)
4.

(6 angles)
5.

(5 angles)
6.

(4 angles)
7.

so we have a parallelogram.

(3 angles)

(2 angles)
8.

(1 angle)
9.
Total Cost = 55+0.35x
X represents the amount of minutes you spend talking on the phone.
(15 x g) + 1
is your answer
hope this helps