通信工程排名文章关键词：通信工程排名二、合并同类项相关例题合并同类项$2x^2y-3xy^2-5x^y+xy+4y^x$解析：$2x^2y-3xy2-5x^2y+xy+4y^x=(2-5)x^2y+(-3+4)xy^2+xy=-3x^2y+xy^2+xy…