Answer:
-4
Step-by-step explanation:
2x + 12 = 18
18 - 12 = 6
2x = 6
x = 3
The maximum number of turning points in a cubic function is 2.
In this case,

The discriminant is

, which means the derivative has no real roots. This means there are no critical points and thus no turning points/relative extrema.
Using sine law:
9/sinc = 15/sin22
sinc = 9sin22 / 15 = 0.225
so c = sin^-1(0.225) = 12.99 degrees ~~ 13 degrees
if B was required:
B = 180 - C - A ~~ 145
-12/4= -3
18/5= 3.6
-2.5= -2.5
1/5= .2
10= 10
Ordered) -12/4, -2.5, 1/5, -2.5, 10
The median is 1/5 since it's in the middle of all five numbers.
Hope I could help! :)