Trapezoid RSTU with vertices R(-11,1),S(-5,3), T-5,-3)and U(-11,-3): k=3/2, centered at (-13,-5)

What is the sum of the geometric series in which a1 = 7, r = 3, and an = 1,701? hint: cap s sub n equals start fraction a sub one left parenthesis one minus r to the power of n end power right parenthesis over one minus r end fraction comma r ≠ 1, where a1 is the first term and r is the common ratio