Find the sum of the infinite geometric series, if it exists. 4 - 1 + 1/4 -1/6 + a. - 1 b. 3 c. 1/6 d. does not exist

Consider this expression and the steps to evaluate it. 4^5(−2)^9/4^8(−2)^3 1. apply the quotient of powers:      (−2)^a/4^b 2. evaluate powers:           c/d select the value of each variable. a = _ b = _ c = _ d = _