Simple....
you have:

You're trying to find b..so isolate it...

leaving you
a=c*b
still not done....


Thus, your answer.
Answer:
The correct set of equations is C.
Step-by-step explanation:
m + n = 32
m = 3n
We have 4n = 32, so n = 8 and m = 24.
Answer:

Step-by-step explanation:
We have a similarity of triangles. Once the side BC and ED are parallel,


Once 



