Подстановка условия
[src]z - 3*z/20 - (z + y)/5 - ((21*x)/5)*(z + y)/100 - y при y = 1/3
z - 3*z/20 - (z + y)/5 - ((21*x)/5)*(z + y)/100 - y
$$- y + - \frac{21 x}{500} \left(y + z\right) + - \frac{y}{5} + \frac{z}{5} + z - \frac{3 z}{20}$$
z - 3*z/20 - (z + (1/3))/5 - ((21*x)/5)*(z + (1/3))/100 - (1/3)
$$- (1/3) + - \frac{21 x}{500} \left((1/3) + z\right) + - \frac{(1/3)}{5} + \frac{z}{5} + z - \frac{3 z}{20}$$
z - 3*z/20 - (z + 1/3)/5 - ((21*x)/5)*(z + 1/3)/100 - 1/3
$$- \frac{21 x}{500} \left(z + \frac{1}{3}\right) + - \frac{z}{5} + \frac{1}{15} + z - \frac{3 z}{20} - \frac{1}{3}$$
-2/5 + 13*z/20 - 21*x*(1/3 + z)/500
$$- \frac{21 x}{500} \left(z + \frac{1}{3}\right) + \frac{13 z}{20} - \frac{2}{5}$$