Does every positive real number have both a positive and negative cube root?

6(2x+y)+2(x+4y) how can i solve this

Find the volume of the solid generated when the region bounded by y= x and y= 4√x is revolved about the x-axis the volume of the solid is: (type an exact answer cubic units)

Find the sum of the measure of the interior angles of a polygon of 9 sides ; of 32 sides