Arianna and her children went into a grocery store where they sell peaches for $1 each and mangos for $0.50 each. Arianna has $9 to spend and must buy at least 13
peaches and mangos altogether. If a represents the number of peaches purchased
and y represents the number of mangos purchased, write and solve a system of
inequalities graphically and determine one possible solution.

i hope this is what you were looking for.

see attached graph

we need to see the graph to know but

strong positive is if it is going up from left to right in a straight diagonal line (like this /)

strong negative is the same but from right to left (like this \)

weak negative is the same as strong negative but its more straight line still right to left

and weak positive is the same as strong positive but more a straight line still left to right though.