Answer: 
Step-by-step explanation:
The first thing you must remember is the mulplication of signs. You know that:

You can observe that the number inside the parentheses is positive (+) and the sign that is outside the parentheses is negative (-), therefore, when you multiply these signs you get a negative sign (-). Then you get:

Now, you need to add these numbers. And the result obtained is:

I can help, just explain the question and what you don’t understand!
Hey there!
The interior angles of a triangle equal 180.
We can use this and the measures of the angles we are given to find the missing interior angle.
50+93=143
180-143=37
Since the missing angle (37) and angle x are supplementary, they add up to 180 as well.
37 + x = 180
180 - 37 = 143
x = 143
Hope this helps!
1) The ratio of used books to all books is 6:14
2) The ratio of used books to new books is 6:8
Any context to this question?