What is the value of x

Asequence is a function whose is the set of natural numbers

Solve 2x − 1 = 11 for x using the change of base formula log base b of y equals log y over log b.

Acone is placed inside a cylinder. the cone has half the radius of the cylinder, but the height of each figure is the same. the cone is tilted at an angle so its peak touches the edge of the cylinder’s base. what is the volume of the space remaining in the cylinder after the cone is placed inside it?