Represent the geometric series using the explicit formula. 12, -36, 108, -324,...
Of(n) = f(n-1).(-3)
Of(n) = f(n-1). (3)
Of(n) = 12 • (-3)(n-1)
Of(n) = 12 - (3)(n-1)

1. isolate the variable, in this case, d. subtract 35.5 on both sides of the equation.2. 52 subtracted by 35.5 is 16.53. therefore your answer would be d= 16.5this is the basics of pre algebra, isolating variable through adding, subtracting, multiplying, and dividing, if you have any other questions to ask just comment!

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