1 2 1 x)=x²y + xy²+2xyz 5 5 = 35

x) $$\frac{1}{7}x^2y + \frac{1}{5}xy^2 + \frac{1}{35}xyz = \frac{1}{35}xy(5x + 7y + z)$$.

Ответ:$$\frac{1}{35}xy(5x + 7y + z)$$.