Question

Розвяжіть систему рівнянь. способом додавання 3x2-xy=10 x2-xy=2

Answer 1

$\displaystyle\bf\\\left \{ {{3x^{2} -xy=10} \atop {x^{2} -xy=2 \ |\cdot(-1)}} \right. \\\\\\+\left \{ {{3x^{2} -xy=10} \atop {-x^{2} +xy=-2 }} \right. \\-----------\\2x^{2} =8\\\\x^{2} =4\\\\x_{1} =-\sqrt{4} =-2 \ \ \ ; \ \ \ x_{2} =\sqrt{4} =2\\\\\\x^{2} -xy=2\\\\xy=x^{2} -2\\\\\\y=\frac{x^{2} -2}{x} \\\\\\y_{1} =\frac{(-2)^{2} -2}{-2} =-\frac{4-2}{2} =-1\\\\\\y_{2} =\frac{2^{2} -2}{2} =\frac{4-2}{2} =1\\\\\\Otvet \ : \ (-2 \ ; \ -1) \ \ , \ \ (2 \ ; \ 1)$