Please help me, i am confused on letter C

Find the value of x that will make l ll m

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.

Solve the inequaliy: (x^2+2)(x−2)^2(6−2x)> 0