I need help with these questions

12. Let R be the shaded region bounded by the graph of y = vx , the graph of y = x -2, and the x-axis, as shown in the figure above. Which of the following gives the volume of the solid generated when R is revolved about the x-axis? (A) x ] ( x -(x-2)?) dx (B) x ] ( VX - (x - 2)? ) dx (Cafxax + x](x -(x-2)' ) dx (D) njxax + x ](Vx-(x-2)') dx lue o 14. Which of the following integrals represents the volume of the solid formed by revolving the region bounded by the graphs of y = x' , y = 1, and x = 2 about the line y = 10? (A) 2x f (10-y)(2 -Vy)dy (B) x ] [81-(10-x')2 ] dx ? (c x] [9-(10-x') ]dx (D) x ] [1-(10-x)2 ] dx ? 15. The base of a solid is the region enclosed by y = e" and the lines y = 1 and x = In 3. Cross sections perpendicular to the y-axis are squares. Write an integral that represents the volume of the solid. (A) (ex - 1) dx (B) x f (In3 -Iny) dy (c j(In3 -my) dy (D) ] (In3-my)dy