SALEM – A Peabody woman who was able to talk her way out of a stiff jail term in 2010 on credit fraud and passing fake checks pleaded guilty to drug charges Thursday.Joanna Snyder, 48, of 14 Aberdeen Ave., changed her plea of innocent to guilty Thursday in Salem Superior Court to two counts of distribution of heroin as well as possession with the intent to distribute heroin before Judge John T. Lu.Snyder told Lu that she is a heroin user and the drugs were for personal use.Snyder was sentenced to serve 4 to 41/2 years in state prison before being placed on three years of probation.The assistant district attorney stated that the charges arise from her arrest on April 28 following a month-long investigation.Between April 21 and April 25 Snyder twice sold heroin to an undercover officer for $120 each, one of them in a 7-Eleven convenience store parking lot on Lynn Street and another from her home.Then on April 28, police raided her home on Aberdeen Avenue and seized 8 grams of heroin found in a hidden false bottom of a hair spray can, along with a scale and approximately $800 in cash, believed to be proceeds from drug sales.