Let x1,x2,x3 be random sample of normal(6,4)(x+1)/2,-1<x<1,find P(max{x1,x2,x3}>8)

It looks to me this is an incompatible mixture of the two previous problems.

f(x)≠(x+1)/2 if X~N(6,4).
Please explain or elaborate if I am mistaken.