Consider the following geometric sentence. -5,10,-20,40. if the explicit formula for the sequence above is expressed in the form an= b×c^n-1, determine the values of b and c

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 = _