Sam’s height is 1.58 m. His younger brother Tom’s height is 0.4 m less than his height. What is Tom’s height? A)1.58 m B) 1.54 m C)1.98 m D) 1.18 m

Find the volume of the solid obtained by rotating the region enclosed by the curves y=1x and y=7^-x about the x-axis. (use symbolic notation and fractions where needed.) volume =