样例： E=(xy)'z)'(x'+z)y+z) Step 1.Using DeMorgan's laws and involution,we obtain E=(xy"+z)(x'+z)/+(y+z))=(xy+)xz'+yz) Step 2.Using the distributive laws,we obtain E=xyxz+xyyz+xz''+yzz' Step 3.Using the commutative,idempotent,and complement laws,we obtain E=xyz'+xy+x+0 Step 4.The product x'is contained in xy';hence,by the absorption law, x+(xz'y)=xz Finally: E=xy+xz样例： Finally：