Rewrite these fractions so they have a common denominator. 3/5 and 7/15

[10 points, algebra 2]according to my answer key the restrictions are -1 and 4. but why not positive 1?

Use composition to determine if (x) or h(x) is the inverse of f(x) for the limited domain x2-1.

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.