Which graph represents the equation y= -x^2 -2

a. i
b. ii
c. iii
d. iv

give a detailed reason and answer for each graph

Lizette is training for a marathon. at 7: 00 she left her house and ran until 8: 30, then she walked until 11: 30. she covered a total distance of 18 miles. her running speed was six miles per hour faster than her walking speed. find her running and walking speeds in miles per hour.