How many four-digit numbers can you form from the numbers 1, 2, 3, 4, 5, 6, 7, 8, and 9 (a) if you use each digit only once? (b) if you can repeat each digit?

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)

news channels,news papers,and the internet

ummm seems that u didnt post the attachement !