Since the hiker can move in any direction, the equation that represent the area in which the hiker could be will be the equation of circle with radius r=12 and center (5,10)
The equation of a circle with radius r and center (h,k) is:

The only thing we have left is replace the values to get:

Answer:
o.6x- 0.42857142857
Step-by-step explanation:
4a + 3 - 9 = -7 + 2 + a
4a - 6 = -5 + a
4a - a = -5 + 6
3a = 1 / : 3
a = 1/3