I'm not sure how this get to line 3 from line 2.(How does the intergral work)

Now the marginal posterior distribution of u can be obtained by direct integration:| (n-1)s2 p( uly ) = / 2 (02 ) n+1 exp (n - 1)$2 Vn n( u - 5) 2 202 V2no exp 202 (n-1)s2 ) n-1 do2 = 2 Vn ( 02 ) 3 +1exp (n - 1)s2 +n ( M - 5) ) do2 202 (n-1)$2) 21 = 2 Vn r(") r(25) V2n (n-1)$2 +n (1-1)2] 2 (n-1)s2 1 51 = 2 Vn r ( ") T("2) V2n = r (") r(21) (n-1)RS/ Vn I+ AD ( MOV ) 271/2 (7.6)