This is the concept of Algebra, the number of books Samantha has will be:
Number books Deanne has is d
Number of books Samantha has 4d+3
Answer: Samantha has (4d+3) books
<u>Hello:</u>
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<u>Okay, this problem should be taken in a series of steps</u>:
<u>What is the slope's formula?</u>

- (x₁,y₁) -- first point
- (x₂,y₂) -- second point
<u>Okay, now let's use this knowledge</u>
10. (5,-19) and (-5,21)

11. (12,1) and (12, -1)

12. (8,7) and (4,7)

<u>Answer:</u>
- Question 10: -4
- Question 11: undefined
- Question 12: 0
Hopefully that helps!