Answer:
a₅ = -43
Step-by-step explanation:
You can automate this with Excel.
In cell A1, type -7.
Then, in cell A2, type =, click A1 and type -9.
Next, drag the cell A2 down, until you pass A5.
if you want to do it by hand:
a₁ = -7
a₂ = a₁ - 9 = -7 - 9 = -16
a₃ = a₂ - 9 = -16 - 9 = -25
a₄ = a₃ - 9 = -25 - 9 = -34
a₅ = a₄ - 9 = -34 - 9 = -43
