Question

what is the 4th term in the sequence b(n)=1(-2)^n-1

Answer 1

$b(n)=1(-2)^n-1$

When n = 4, 
$b(4)=1(-2)^4-1$

$b(4)=16-1$

$b(4)=15$

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$b(n)=1(-2)^{n-1}$

When n = 4
$b(4)=1(-2)^{4-1}$

$b(4)=1(-2)^3$

$b(4)=1(-8)$

$b(4)=-8$