HELP SOMEONE FOR 20 POINTS

Factor and solve to find roots x squared -x - 90 =0

28 x 12 + 34 = ? it's for a test that if i fail on i will not proceed into the honor roll society i always dreamed of!me! worth 50 !

Randy and trey take turns cleaning offices on the weekends. it takes randy at most 4 hours to clean the offices. it takes trey at most 6 hours to clean the offices. what is the greatest amount of time it would take them to clean the offices together? 2.4 hours 2.5 hours