Find the slope of the line

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.

Gabrielle's age is two times mikhail's age. the sum of their ages is 84. what is mikhail's age?

Alex's monthly take home pay is $2,500. what is the maximum bad debt payment he can maintain without being in credit overload?