Question

Va rog frumos putin ajutor la exercitiul de mai jos

Answer 1

 

$\displaystyle\bf\\\begin{cases}2x-y=3\\x^2+2x-7=y\end{cases}\\\\\\2x-(x^2+2x-7)=3\\\\\underline{2x}-x^2-\underline{2x}+7=3\\\\-x^2+7=3\\\\-x^2=3-7\\\\-x^2=-4~~~\Big|~\cdot(-1)\\\\x^2=4\\\\x^2-4=0\\\\(x+2)(x-2)=0\\\\x+2=0\implies~x_1=-2\\y_1=2x-3=2\cdot(-2)-3=-4-3=-7\\\\x-2=0\implies~x_2=2\\y_2=2x-3=2\cdot2-3=4-3=1\\\\Solutia~1:~~\boxed{\bf~x_1=-2~si~y_1=-7}\\\\Solutia~2:~~\boxed{\bf~x_2=2~si~y_2=1}$