Harita must memorize 90 measures of music for her cello solo at a concert. she plans on memorizing 18 new measures for every 3 days of practice. which equation can be used to determine  m, the number of measures harita still needs to memorize, as a function of  d, the number of days of practice since she began learning the piece? m  = 72 – 15dm  = 90 – 6dm  = 101 – 21dm  = 108 – 3d