1．　If　x　and　y　are　integers　and　xy＋x＾2　is　oddh　which　of　the　following　statements　must　be　true?①　x　is　odd②　y　is　odd③　x＋y　is　oddA．　①B．　③C．　①　and　②D．　①　and　③E．　②　and　③2．　For　how　many　integers　n　is　（2n＋1）（3n－1）　a　negative　number?A．　NoneB．　OneC．　TwoD．　ThreeE．　Four求详解