Find the steady-value of r_t

[E574]

You estimate the following model:
rt=1.5+1.3rt-1-0.6rt-2+et
var(et)=0.16

a) Find the steady-value of rt.

My answer is based on the formula for the steady-state (long-run) growth rate:

rL=b_0+b1 rL+...+bk rL
so that
rL=b0/(1-b1-b2-...bk)

rL=1.5/(1-1.3+0.6)=5

What should I do with et and var(et)=0.16?

Thank you.

[BGM]

I am not sure about the word "steady-value" here.
But I assume it is the long run time average of the time series

For an ergodic time series, it will converge to

Note the white noise process satisfy , and by the stationarity
we have

Taking expectation on both sides, rearranging terms will yield the desired equation.