Marco is in charge of buying prizes for a class competition. He purchased a total of 105 items made up of three dollar necklaces and two dollar buttons. The total cost for the items was $285 Write a system of equations to represent this situation was necklaces (n) and buttons (b)

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for finding the midpoint of any given 2 pair of points simply add the respective x coordinates with other x coordinate and the y coordinate with other y coordinate and divide them by 2

in your question it will be :

(3+1)/2 for the x coordinate of mid point i.e 2

[8+(-4)]/2 for the y coordinate of midpoint i.e 2

so coordinates of mid point of points (3,8) and (1,-4) will be (2,2)