Solve {l}{x-y+ztext{restar-}11y+31y-8y-19y}{-a^{2}b+6a^{3}b^{3}-18ab^{5}+b^{2}text{restar}-8a^{6}+9b^{6}-11a^4b^2-11a^2b^4}

$$\left. \begin{array} { l } { x - y + z \text { restar- } 11 y + 31 y - 8 y - 19 y } \\ { - a ^ { 2 } b + 6 a ^ { 3 } b ^ { 3 } - 18 a b ^ { 5 } + b ^ { 2 } \text { restar } - 8 a ^ { 6 } + 9 b ^ { 6 } - 11 a ^ { 4 } b ^ { 2 } - 11 a ^ { 2 } b ^ { 4 } } \end{array} \right.$$

Evaluate

$$b^{2}\left(-Im(s)\left(Re(t)\left(Re(a)Im(r)+Re(r)Im(a)\right)+Im(t)\left(Re(a)Re(r)-Im(a)Im(r)\right)\right)+Re(s)\left(-Im(t)\left(Re(a)Im(r)+Re(r)Im(a)\right)+Re(t)\left(Re(a)Re(r)-Im(a)Im(r)\right)\right)-11a^{4}\right)+z\left(-Im(s)\left(Re(t)\left(Re(a)Im(r)+Re(r)Im(a)\right)+Im(t)\left(Re(a)Re(r)-Im(a)Im(r)\right)\right)+Re(s)\left(-Im(t)\left(Re(a)Im(r)+Re(r)Im(a)\right)+Re(t)\left(Re(a)Re(r)-Im(a)Im(r)\right)\right)\right)+6\left(ab\right)^{3}-11a^{2}b^{4}-18ab^{5}+9b^{6}-8a^{6}-ba^{2}+x-8y$$