You have to build an equation to find the answer,
angles in a straight line add upto 180° 
so your equation would be,
12x+30°=180°
      -30    -30
=12x=150°
   ÷12  ÷12
=x=12.5°
now find the measures of the angles by using 12.5 as x.
angle EAF= 2x
                 =2×12.5
                 =25° degrees
angle DAE= 4x
                 =4×12.5
                 =50°degrees
angle CAD=6x
                 =6×12.5
                 =75°degrees
check,
30+25+50+75=180°degrees
hope this helps.......
        
             
        
        
        
Answer:

Step-by-step explanation:
we know that
The equation of a exponential growth function is given by 

where
P(t) is the population in Madison
t is the number of years
a is the initial value
b is the factor of growth
we have

substitute

 
        
             
        
        
        
Answer:

Step-by-step explanation:
It is a linear homogeneous differential equation with constant coefficients:
y" + 4y = 0
Its characteristic equation:
r^2+4=0
r1=2i
r2=-2i
We use these roots in order to find the general solution:

 
        
             
        
        
        
She has run 21 miles already. Let t be the number of additional miles added on. 
In total, she has run t+21 miles 
This is going to be set greater than 38 since "Ann will run more than 38 miles"
So we have this inequality
t+21 > 38
we solve for t by subtracting 21 from both sides
t+21 > 38
t+21-21 > 38-21
t+0 > 17
t > 17
The final answer is t > 17
which means that the possible additional number of miles she could run is anything larger than 17. So t = 18 is one possibility.