4a2b2-25=(2ab-5)(5+2ab)
a2b2- это если что a в квадрате и b в квадрате
√2х²+7=х+2 возведем обе части уравнения в квадрат и получим
2х²+7=х²+4х+4
х²-4х+3=0
х1+х2=4
х1*х2=3 х1=3 х2=1
Используем формулу (a+b)(a-b)=a квадрат-b квадрат
4*5-14=6
6sin172°/(cos94°)*cos4°=
6sin8°/(-sin4)*cos4)=3sin4°•cos4°/
(-sin4°*cos4°)
=-3
![\left \{ {{x^{2}+xy-x-y=2}\atop {x-y=2}} \right.\\\left \{ {{y=x-2} \atop {x^{2}+x(x-2)-x-(x-2)=2} } \right. \\\left \{ {{y=x-2} \atop {x^{2}+x^{2}-2x-x-x+2=2}} \right.\\\left \{ {{y=x-2} \atop {2x^{2}-4x=0} } \right.\\\left \{ {{y=x-2} \atop {x^{2}-2x=0} } \right.\\\left \{ {{y=x-2} \atop {x(x-2)=0}} \right.\\\left \{ {{y=x-2} \atop {x=2;x=0}} \right.\\1)\left \{ {x_{1}= 2}} \atop {y_{1}=0} } \right. \\2)\left \{ {{x_{2}=0} \atop {y_{2}=-2} } \right.](https://tex.z-dn.net/?f=%5Cleft+%5C%7B+%7B%7Bx%5E%7B2%7D%2Bxy-x-y%3D2%7D%5Catop+%7Bx-y%3D2%7D%7D+%5Cright.%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7Bx%5E%7B2%7D%2Bx%28x-2%29-x-%28x-2%29%3D2%7D+%7D+%5Cright.+%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7Bx%5E%7B2%7D%2Bx%5E%7B2%7D-2x-x-x%2B2%3D2%7D%7D+%5Cright.%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7B2x%5E%7B2%7D-4x%3D0%7D+%7D+%5Cright.%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7Bx%5E%7B2%7D-2x%3D0%7D+%7D+%5Cright.%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7Bx%28x-2%29%3D0%7D%7D+%5Cright.%5C%5C%5Cleft+%5C%7B+%7B%7By%3Dx-2%7D+%5Catop+%7Bx%3D2%3Bx%3D0%7D%7D+%5Cright.%5C%5C1%29%5Cleft+%5C%7B+%7Bx_%7B1%7D%3D+2%7D%7D+%5Catop+%7By_%7B1%7D%3D0%7D+%7D+%5Cright.+%5C%5C2%29%5Cleft+%5C%7B+%7B%7Bx_%7B2%7D%3D0%7D+%5Catop+%7By_%7B2%7D%3D-2%7D+%7D+%5Cright.)
Ответ: (2 ; 0) , ( 0 ; - 2)