P2y的精选

问题详情：设P=2y－2,Q=2y+3,有2P－Q=1,则y的值是                       (     )A.0.4             B.4            C.－0.4           D.－2.5【回答】B；知...

问题详情：设P=2y－2,Q=2y+3,有2P－Q=1,则y的值是(  )A.0.4                         B.4                            C.－0.4                 ...