00:01
For this here, we essentially want to get rid of the complex fraction.
00:03
So what we want to do is multiply by the common denominator, which would be cd.
00:06
So i'm going to multiply the numerator and denominator by cd.
00:09
So the numerator is just going to be c times d.
00:12
And the denominator, when i multiply, each of the variables are going to cancel.
00:15
So we're going to be left with c plus d.
00:17
So the very first part of this, this would be the expression that would be simplified for part a.
00:22
All right.
00:23
So for part b, we're told that the distance from the lens to the object, maybe photographed is 5 feet.
00:29
And the lens of the film is 0 .75b.
00:32
So we want to find the length of the camera.
00:34
So this is where we need to know is that the f is the focal length and d is the distance between the object.
00:40
Sorry, d is the distance between the object being photographed and c is the distance between the lens of the film.
00:46
So we're going to be putting the 5, which represents the distance from the lens to the object, in for d...