When subtracting these two algebraic expressions, the second expression would be equivalent to: (3x + 7) -
(2x + 4)
O 2x - 4
0 - 2x - 4
0 - 2x + 4
O 2x + 4

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.