Répondre :
a) 8^(n+1)+8^n
=8^1*8^n+1*8^n
=(8+1)*8^n
=9*8^n
b) (8^(n+1)+8^n)²
=(9^8^n)²
=81*8^(2n)
=9²*64^n
=3^4*(2^6)^n
c) (4^n-4^(n-1))³
=(4*4^(n-1)-4^(n-1))³
=(3*4^(n-1))³
=3³*4^(3n-3)
=3³*2^(6n-6)
donc r=6n-6
=8^1*8^n+1*8^n
=(8+1)*8^n
=9*8^n
b) (8^(n+1)+8^n)²
=(9^8^n)²
=81*8^(2n)
=9²*64^n
=3^4*(2^6)^n
c) (4^n-4^(n-1))³
=(4*4^(n-1)-4^(n-1))³
=(3*4^(n-1))³
=3³*4^(3n-3)
=3³*2^(6n-6)
donc r=6n-6