q:I need help with question 14, the picture attached, please!

14 . Suppose X . . ..., In is a random sample from a two - parameter exponential distribution with density function f ( ac ; M1 , 0 ) = - . = exp I - HL J , I Z H, HE R, O _ O. irregular ( a ) Write down the likelihood function ; Family U'S `` pote_ as job , ^ ( b ) Derive the maximum likelihood estimators of " and o ; Hiexed Like Function ( C ) Examine whether they are unbiased ; 5. ip Is Cer^ ( d ) Derive their means and variance - covariance matrix* ; ( e ) Derive the distributions of the pivotal quantities #- " and ". _ , where { and } are the MILES of " and o , respectively