a, 1 x 2 x 3 x ... x 8 x 9 - 1 x 2 x 3 x ... x 8 - 1 x 2 x 3 x ... x 7 x 8 x 8
= 1 x 2 x 3 x ... x 8 ( 9 - 1 - 8 ) = 1 x2 x 3 x ... x 8 . 0 = 0
a, 1.2.3...9-1.2.3...8-1.2.3...7.82
= 1.2.3...7.8(9-1-8) = 0
b,\(\frac{3.4.2^{16}}{11.2^{13}.4^{11}-16^9}=\frac{3.2^2.2^{16}}{11.2^{13}.\left(2^2\right)^{11}-\left(2^4\right)^9}\) \(=\frac{3.2^{18}}{11.2^{13}.2^{22}-2^{36}}=\frac{3.2^{18}}{11.2^{35}-2^{36}}\)\(=\frac{3.2^{18}}{2^{35}\left(11-2\right)}=\frac{3.2^{18}}{2^{35}.9}=\frac{1}{2^{17}.3}\)