Complete the recursive formula of the geometric sequence 7\,,-14\,,\,28\,,-56,...7,−14,28,−5 6,...7, comma, minus, 14, comma, 28, comma, minus, 56, comma, point, point, point. a(1)=a(1)=a, left parenthesis, 1, right parenthesis, equals a(n)=a(n-1)\cdota(n)=a(n−1)⋅a, left parenthesis, n, right parenthesis, equals, a, left parenthesis, n, minus, 1, right parenthesis, dot