**4 ^(n + 4) = 4^(n+2+2) = 4^2 {4^ (n+2)}**

so

4^(n+4) - 4^(n+2) = 4^2 {4^ (n+2)} - 4^ (n+2) = 960........................i

facting out 4^ (n+2) eqn i becomes

4^ (n+2) [(4^2)-1] = 4^ (n+2)[16-1] = 4^ (n+2) [15] = 960................ii

dividing by 15 both sides of eqn ii

4^ (n+2) = 64 but 64 = 4^3, so

4^ (n+2) = 4^3, which makes

n+2 = 3, giving

**n = 1**