It can be convenient to let a spreadsheet do the tedious arithmetic. Put the appropriate value where n is in the formula, then do the arithmetic in each case. See the attached for the term values (in columns).
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You need to be careful with problem 5 in a spreadsheet. Many of them improperly evaluate n*(-2^n) as n*(-2)^n, rather than as n*(-(2^n)). The order of operations requires the exponentiation be done first, before multiplication (by -1 in this case). Hence -2^n should always be evaluated as -(2^n). For spreadsheet purposes, problem 5 is better written as -n*2^n.