代数式3x3y-5x6y3z+4xy2-5按x的降幂排列为___________.
计算:(﹣2x2y)3÷2x4y2= .
计算:6x2y3÷2x3y3= .
计算:x6y2÷x3= .
计算:8x2y5÷2xy2= .
计算:(4ab)÷(﹣2a)= .