Question

if an =(n-1) (n-2), then a1=

Answer 1

here n = 1

so a1 = (1-1) (1-2)

         = (0) (-1)

         = -1

   hope it helps u...

Answer 2

n-1=0
n=1

Now,
a1= (1-1) (1-2)
a1= (0) (-1)
a1=0