Which is the graph of f(x) = 5(2)x?

Assuming the function is f(x) = 5(2)^x, then the answer is the graph with the point (2,20) on the curve.

Plugging in x = 2 leads to y = 20
y = 5(2)^x
y = 5(2)^2 ... replace x with 2
y = 5(4)
y = 20
Which is why (x,y) = (2,20) is on the function curve.