Need the point (a, b) lies in the third quadrant on the graph of the line y= 2x+1. find a and b given that the distance from (a, b) to the origin is square root of 65

Mallory has been offers two different jobs. she can baby sit for 6 hours a week and get $8.50 an hour. or she can work at the library for 14 hours a week and make $5.50 an hour. which job will allow her to save the most money after 6weeks?