William W. answered • 11/22/20

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The first term is when n = 1

a_{1} = (-1)^{1+1}(1 + 6)

a_{1} = (-1)^{2}(7)

a_{1} = (1)(7) = 7

The second term is when n = 2:

a_{2} = (-1)^{2+1}(2 + 6)

a_{2} = (-1)^{3}(8)

a_{2} = (-1)(8) = -8

The third term is when n = 3

a_{3} = (-1)^{3+1}(3 + 6)

a_{3} = (-1)^{4}(9)

a_{3} = (1)(9) = 9

The fourth term is when n = 4:

a_{4} = (-1)^{4+1}(4 + 6)

a_{4} = (-1)^{5}(10)

a_{4} = (-1)(10) = -10