分解因式:a2+5a﹣6= .
计算:(m6n3-6mn5)÷(-3mn3)=___________.
计算:(a-1)(b+2)=___________.
计算:-y2·(-y)3=__________.
计算:(2x2-x)-(x2-2x)=________.
如果单项式3xn-1y4与x3ym是同类项,那么n-m的值是________.