Answer:

Step-by-step explanation:
Given

See attachment
Required
Determine the measure of 
and
are on a straight line.
So:
--- angle on a straight line
Substitute known values

Collect like terms


Answer:
The student made the first mistake in step 2.
Step-by-step explanation:
Answer:
In each shelves there are 64/4 books I.e. 16.
You got the b part wrong. It would be 4B+4C/2=4D
Answer:
the amount of matter is mass. how much space you take up
Step-by-step explanation: