题目

Benjamin Franklin was born into a large family. His father, Josiah, was a candle maker. His father wanted him to take over the family business when he grew up, but he wasn't interested. To help Ben decide on a career, Josiah took him on long walks around Boston so he could observe men doing the work of their trade. Benjamin learned how to do many things during these excursions, but he didn't want to pursue（追求，追赶） any of the trades. When Ben was twelve years old his father sent him to his older brother James, who was a printer. Ben worked twelve hours a day in the printing 若关于x的方程x2+3x+k=0的一个根是1，则k的值为    ．