Which is the graph of f(x) = 100(0.7)x?

The graph of f(x) passes through (0,100) points (2,49)  

So option (a) is correct

We have to identify that out of the following given graphs which graph represents the function

The given graphs pass through  two points . If the graph passes through a point , the point will satisfy the equation of graph. The points  can be determined  on observing from the graphs we can plug in the x coordinates

on putting x =0 in to the given function we get

So the graph of f(x) passes through (0,100)

Also putting x = 2 in the function equation we  get

So the also passes through (2,49)  

The graph of f(x) passes through (0,100) points (2,49)  

So option (a) is correct

For more information please refer to the link below

link

use this formula:

p(a\b) = p(a and b)/p(b).

take it from here.