解:(1)*pi p x pyi i ip*px11yi*pAyxAA*pByxBB40x /A125.42xA120x /Bx 1B30.734联立求解得:xA .6667 ,xB117.39 3333p*px11yi400.2590.257kPa0.252kPa* *(2) p pA xA pB xB { 40xA 120(1 xA )} kPa 100kPa所以有 x A=0.25 , x B=0.75*p x 40 0.25A AyA ....