Find Image & Object Distances from h, h', f

[tre.benjamin]

length. I was asked to find the image and the object distance. I didnt think it was possible till i found this

M=h'/h=-q/p : I knew this

q=-ph'/h : I understood how they did this

1/p+1/q=1/f : I knew this

1/p+1(-ph'/h)=-1/f : This i understood also, but how they came up with this next step i have no idear.

1/p(1-h/h')=1/f :Then,

p=f(1-h/h') : smh i just need some kind of explanation then i will be able to sleep

 

[da_nang]

1/p+1/(-ph'/h)=1/f

1/p - h/(ph') = 1/f |factor 1/p

(1/p)(1-h/h') = 1/f |/(1-h/h')

1/p = 1/[f(1-h/h')]

p = f(1-h/h')