Conic section for 5x^2+8y^2+3x+4y+5=0

How do i multiply two digit numbers

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.

Which property was used to simplify the expression? 3c+9 +4c=3c+4c+9