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Пусть
, тогда
![(t-1)(t+2)=40,\t^2+2t-t-2=40,\t^2+t-42=0,\D=1-4cdot1cdot(-42)=1+168=169,\\t_{1,2}=frac{-1pmsqrt{169}}{2}=frac{-1pm13}{2},\\t_1=frac{-1+13}{2}=6,\\t_2=frac{-1-13}{2}=-7.\\\1) x^2+x=6,\x^2+x-6=0,\D=1+4cdot6=25,\\x_1=frac{-1+sqrt{25}}{2}=frac{-1+5}{2}=2,\\x_2=frac{-1-5}{2}=-3; (t-1)(t+2)=40,\t^2+2t-t-2=40,\t^2+t-42=0,\D=1-4cdot1cdot(-42)=1+168=169,\\t_{1,2}=frac{-1pmsqrt{169}}{2}=frac{-1pm13}{2},\\t_1=frac{-1+13}{2}=6,\\t_2=frac{-1-13}{2}=-7.\\\1) x^2+x=6,\x^2+x-6=0,\D=1+4cdot6=25,\\x_1=frac{-1+sqrt{25}}{2}=frac{-1+5}{2}=2,\\x_2=frac{-1-5}{2}=-3;](https://tex.z-dn.net/?f=%28t-1%29%28t%2B2%29%3D40%2C%5Ct%5E2%2B2t-t-2%3D40%2C%5Ct%5E2%2Bt-42%3D0%2C%5CD%3D1-4cdot1cdot%28-42%29%3D1%2B168%3D169%2C%5C%5Ct_%7B1%2C2%7D%3Dfrac%7B-1pmsqrt%7B169%7D%7D%7B2%7D%3Dfrac%7B-1pm13%7D%7B2%7D%2C%5C%5Ct_1%3Dfrac%7B-1%2B13%7D%7B2%7D%3D6%2C%5C%5Ct_2%3Dfrac%7B-1-13%7D%7B2%7D%3D-7.%5C%5C%5C1%29+x%5E2%2Bx%3D6%2C%5Cx%5E2%2Bx-6%3D0%2C%5CD%3D1%2B4cdot6%3D25%2C%5C%5Cx_1%3Dfrac%7B-1%2Bsqrt%7B25%7D%7D%7B2%7D%3Dfrac%7B-1%2B5%7D%7B2%7D%3D2%2C%5C%5Cx_2%3Dfrac%7B-1-5%7D%7B2%7D%3D-3%3B)
![2) x^2+x=-7,\x^2+x+7=0,\D=1-4cdot1cdot7=1-28=-27 textless 0 2) x^2+x=-7,\x^2+x+7=0,\D=1-4cdot1cdot7=1-28=-27 textless 0](https://tex.z-dn.net/?f=2%29+x%5E2%2Bx%3D-7%2C%5Cx%5E2%2Bx%2B7%3D0%2C%5CD%3D1-4cdot1cdot7%3D1-28%3D-27+textless++0)
нет действительных корней.
![OTBET: x_1=2, x_2=-3. OTBET: x_1=2, x_2=-3.](https://tex.z-dn.net/?f=OTBET%3A+x_1%3D2%2C+x_2%3D-3.)
нет действительных корней.
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