Graph a line that is perpendicular to y=7/8x+3

Rewrite the following without an exponent. (5/8)-1

100 points, hi, i’m not sure how to get the equation from the graph and table.

The volume of a spherical hot air balloon v(r) = 4 3 ? r3 changes as its radius changes. the radius is a function of time given by r(t) = 3t. find the instantaneous rate of change of the volume with respect to t at t = 2.