Answer:
12
Step-by-step explanation:
2xy+15x
Let x=4 and y= -9
2(-4)(-9) + 15(-4)
Multiply
72 -60
Subtract
12
Answer: 
Step-by-step explanation:
Given
The plane is cruising at an altitude of 
The angle of depression is 
Suppose the distance of the plane to the runway is x
from figure

1-5 through the given lines its 1-5 if not then its kinda difficult can i get a picture
You start off with 4*(cos(x+(pi/3)))
Let's place the 4 aside for the time being:
Cos(u+j) = cos(u)*cos(j) - sin(u)*sin(j)
cos(x+(pi/3)) = cos(x)*cos(pi/3) - sin(x)*sin(pi/3)
cos(x+(pi/3)) = cos(x)/2 - (sqrt(3)/2)*sin(x)
Multiplying by the 4 we put aside:
4*cos(x+(pi/3)) = 2*cos(x) - 2*sqrt(3)*sin(x)
The correct answer is B