Question

(5−1)⋅(5+1)⋅(5^2+1)⋅(5^4+1)⋅(5^8+1)−5^16+31

Answer 1

$(5-1)(5+1)(5^2+1)(5^4+1)(5^8+1)-5^{16}+31$$=(5^2-1)(5^2+1)(5^4+1)(5^8+1)-5^{16}+31$$=(5^4-1)(5^4+1)(5^8+1)-5^{16}+31=(5^8-1)(5^8+1)-5^{16}+31$$=5^{16}-1-5^{16}+31=31-1=30$