9y²+6y-9y-6+18y-12+6y²-4y=18y²-8

\[ 15y^2+11y-18=18y^2-8 \] \[ 3y^2-11y+10=0,\quad D=121-120=1 \] \[ y=\frac{11\pm1}{6} \] Ответ: \(\displaystyle y=\frac{5}{3};\ 2\).