√61. You would use the distance formula. The works in the picture
10(h)+5(h)+7, because 10 and 15 are charged per a hour, so they have a h(house). 7 dollars is a fee that you only pay once. I hope this helps :)
To find the midpoint of a segment you need to use this equation:
(x1+x2/2, y1+y2/2) so if you plug in the numbers its...
9+(-7)/2, 2+(-9)/2
then solve to find x and y coordinate
x= 1 and y= -3.5
so the midpoint of CD is (1,-3.5)
The correct answer would be a and c