Answer this question! i am having some trouble in khan..

What is the measure of ac? 5 units 13 units 26 units 39 units 3x- 2b 6x + 9

Solve the equation by completing the square. x^2+2x=17

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.