\frac{ x^{2} -4}{3}- \frac{6-x}{2}=3
\frac{2 x^{2} -8-18+3x}{6}=3
2 x^{2} +3x-26=18
2 x^{2} +3x-26-18=0
2 x^{2} +3x-44=0
D=b ^{2}-4ac
D=3 ^{2}-4*2*(-44)=9+352=361
x_{1}= \frac{-b+ \sqrt{D} }{2a}
x_{1}= \frac{-3+ \sqrt{361} }{2*2}= \frac{-3+19}{4}= \frac{16}{4}=4
x_{2}= \frac{-b- \sqrt{D} }{2a}
x_{2}= \frac{-3-19}{4}= \frac{-22}{4}=- \frac{11}{2}=-5 \frac{1}{2}=-5.5
Ответ: x_{1}=4 , x_{2}=-5.5