Good morning, could you help me solve the following relativity problem describing in detail the reference systems and st

[answerhappygod]

Good morning, could you help me solve the following relativity
problem describing in detail the reference systems and step by step
the developments?
They told me that they are simple problems but the truth is that
they were difficult for me. Thanks in advance.
-Two ships A and B are moving in the same direction. From the
ground, spacecraft A is moving at 0.8c and B at 0.9c. How fast is
ship B traveling from ship A?
-Two jets of material are ejected in opposite directions from
the center of a radio galaxy. Both jets move with a speed of 0.750c
relative to the galaxy. Determine the speed of one jet relative to
the other.