a,\(=\left(2-1\right)\left(2+1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)=\left(2^2-1\right)\left(2^2+1\right)\left(2^4+1\right)\left(2^8+1\right)\)
\(=\left(2^4-1\right)\left(2^4+1\right)\left(2^8+1\right)=\left(2^8-1\right)\left(2^8+1\right)=2^{16}-1\)
b,\(=\left(2^3-1\right)\left(2^3+1\right)\left(2^6+1\right)\left(2^{12}+1\right)\left(2^{24}+1\right)\)
tiếp tục giống bài a
c, \(=\left[x^2-\left(x-1\right)\right]\left[x^2+\left(x+1\right)\right]\left(x^2-1\right)=\left(x^2-x^2+1\right)\left(x^2-1\right)=x^2-1\)