Die partiellen Ableitungen erst mal:
$$ \frac{\partial \, Z}{\partial \, x}=β_1+2 β_3x+β_4y+3 β_6x^2+2β_7xy+β_8y^2 $$
$$ \frac{\partial \, Z}{\partial \, y}=β_2+β_4x+2β_5y+β_7x^2+2β_8xy+3β_9y^2 $$
Die partiellen Ableitungen erst mal:
$$ \frac{\partial \, Z}{\partial \, x}=β_1+2 β_3x+β_4y+3 β_6x^2+2β_7xy+β_8y^2 $$
$$ \frac{\partial \, Z}{\partial \, y}=β_2+β_4x+2β_5y+β_7x^2+2β_8xy+3β_9y^2 $$