Алгебра: Помогите решить №4 и №6

4)1) $\frac{ 2^{8}* 25^{8} }{ 50^{6} } = \frac{ 2^{8}* 25^{8} }{ 2^{6}* 25^{6} } = 2^{2} * 25^{2} =4*625=2500$
2) $\frac{ 11^{4} *5^{6} }{ 55^{4} } = \frac{ 11^{4} *5^{6} }{ 11^{4} * 5^{4} }= \frac{ 5^{6} }{ 5^{4} } = 5^{2}=25$
6)1) $\frac{18sin 40*cos 40}{sin 80} = \frac{9sin 80}{sin 80} =9$
2) $\frac{46sin 165*cos 165}{sin 330} = \frac{23sin 330}{sin 330} =23$
3) $\frac{6cos 207}{cos 27} = \frac{6cos(180+27)}{cos 27} = \frac{-6cos 27}{cos 27} =-6$