Diamond used a number line to add. She started counting at 8, and then she counted until she was on -5 on the number line. If Diamond is modeling addition, what number did she add to 8 in order to get to -5

-13

Step-by-step explanation:

If Diamond was using addition, then the only number that can be added to 8 in order to get -5 would be -13. This is because 13 is 5 more than 8. Therefore, a negative 13 (-13) added to 8 would mean that you would have to move to the left of the number line 13 places which would cause you to pass 0 by a total of 5 spaces to the left, leaving you at -5

to get the y-intercept of any function, we simply set x = 0 and solve for "y", bearing in mind that x = 0 at that point.