Answer: She bought 68 books.
Step-by-step explanation:
Subtract 31 from 99 to find the difference! The difference tells us how many books she bought at the yard sale.
A in the answer for this question
Thank you
-3 + 7 = 4
4 - 7 = -3
I think that's what you want.
Answer/Step-by-step explanation:
7. Line 1 = undefined.
Slope of a vertical line is always undefined. The run is zero as x-coordinate remains the same.
8. Line 2 = 




9. Line 3 = 




10. Line 4 = undefined (slope of a vertical line is always undefined)
11. Line 5 = 



12. Line 6 = 




13. Line 7 = 0
An horizontal line has no rise.
14. Line 8 = 0 (slope of horizontal line is always zero)
15. Line 9 = undefined (slope of a vertical line is always undefined)
16. Line 10 = undefined (slope of a vertical line is always undefined)
17. Line 11 = 0 (slope of horizontal line is always zero)
18. Line 12 = undefined (slope of a vertical line is always undefined)