若单项式-6ax-2b与1/2a3b3-y是同类项,则(x2-y3)-(y-x)的值为_.

问题描述:

若单项式-6ax-2b与

1
2
a3b3-y是同类项,则(x2-y3)-(y-x)的值为______.

若单项式-6ax-2b与

1
2
a3b3-y是同类项,
则x-2=3,3-y=1,
解得x=5,y=2,
则(x2-y3)-(y-x)=52-23-2+5=20.