A picture frame is usually a square or rectangle, right? So that means two of the sides had to have a length of 18 centimeters. So, we multiply 18 by 2 and subtract (because we have to add all the sides to get the perimeter) that answer from the perimeter. We come out with 72. Now we have to divide 72 by 2 because there were 2 other sides. 72 divided by 2 comes out to be 36. The picture frame was 36 centimeters wide :) Hope this helps you!
Whenever we have an exponent of <em>x</em>, it is a exponential function. The 5 is simply the base of the exponent and the 6 means we are vertically stretching the graph by a factor of 6.