Since b is a variable ( unknown) we replace b with 8 since its given to us so the equation turns to 8-3-3 which we do 8-3=5-3=2
Answer:




Step-by-step explanation:
Given
See attachment
From the attachment, we have:


First, we need to calculate length LM,
Using Pythagoras theorem:



Collect Like Terms



Solving (a): 


Substitute values for MN and LN


Solving (b): 


Substitute values for LM and MN


Solving (c): 


Substitute values for LN and LM


Solving (d): 


Substitute values for LM and LN


Answer:
Number 1 I think sorry if I am incorrect.