Which function has the domain x greater-than-or-equal-to negative 11

Convert 16 yards to feet use the conversion rate 3 feet = 1 yard

If cos(2x) = tan^2(y), show that cos(2y) = tan^2(x).

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.