The general shape is that of an exponential function. Since the horizontal asymptote is -3, it appears to be shifted down 3. The y-intercept is 1 unit above the horizontal asymptote, so it appears there has been no horizontal shift.
For x=1, the curve goes through a point 6 units above the horizontal asymptote. This suggests the equation is y = 6^x - 3
It's a proportion. 2 is to x as 15 is to 9, or 2/x = 15/9. Multiply the means and extremes 15x = 18 divide both sides by 15 to get x by itself. x = 1.2
