The solution set of the two equations:X+y=0,y-5=0 in R×R is​

Do you mind if you guys me with this question i’m on number 8

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 =

Using only odd number for numerators write two different subtraction problems that have a difference of 3/4