Question

-2, -4 , -8 , -16... find a 11

Answer 1

\[\Large a_n=a_1+(n-1)d\]
\[\Large a_{11}=a_1+(11-1)d\]


To find d:

\( d=a_2 - a_1 \)
Here
\(a_1= -2 \)
\(a_2 = -4 \)

\(d=-4 - (-2)=-4+2= -2 \)

Now plug in the values of \(a_1 \ and \ d \) in the equation & find \(\Large a_{11}\)