Answer:
2nd option
Step-by-step explanation:
given an exponential function in the form y = a
to find a and b use the coordinate points it passes through
using (0, 4 ) , then
4 = a
[
= 1 ] , that is
a = 4 , so
y = 4
using (2, 100 )
100 = 4b² ( divide both sides by 4 )
25 = b² ( take the square root of both sides )
= b , that is
b = 5
then exponential function is
y = 4 . 
Given :
∠ABF = ( 7x + 20 )°
∠FBC=(2x - 5)°
∠ABC= 159°
To Find :
The value of x .
Solution :
Assuming B the center of a circle .
So , all three given angles must be added to 360° .

Therefore , the value of x is 20.67° .
Hence , this is the required solution .
5 cm = 2km
Scale= 5 cm : 200000 cm
= 1 : 40000
a. 1 : 40000 = x : 500000
x = 12.5 cm
b.1 : 40000 = 2 : x
x = 80000 cm
x = 0.8 km