Answer:
it is not always possible to find their intersection point for e.g take
y=x-1 it's inverse is y=x+1 so their is no intersection point but generally u find intersection points by equalizing their functions
f(x)=f^-1(x)
Since both is equal to p(a), you can set them as equal to each other:
15 = 2a - 3
18 = 2a
9 = a
1800000000000000000000000
Number 1 is 0.3 and number two is 1.25
~hope this helps~
