See attachment for question, please help asap

You add on the equation like the example below

Step-by-step explanation:

The sequence is an arithmetic one with first term a1=−4 and difference d=2 . To calculate a9 we use the formula: an=a1+(n−1)⋅d. Here we have: a9=−4+(9−1)⋅2=−4+8⋅2=−4+16=12.