Right, well if we multiply both sides, we multiply  both sides of B  right, by this co-efficient lander alright, we get  right,lander by T minus one,lander erm   right then what we do is that we get beta into lander X T minus one plus  lander squared, X T minus two  lander cubed, X T minus three,and lander to four  X T minus four and so on and so s so on until infinity  right.