[tex] \left\{\begin{array}{ccc}y=x^2-3x\\x=y+8&\to y=x-8\end{array}\right\\\\x^2-3x=x-8\ \ \ |-x\\\\x^2-4x=-8\\\\x^2-2\cdot x\cdot2=-8\ \ \ \ |+2^2\\\\x^2-2\cdot x\cdot2+2^2=-8+2^2\ \ \ |\text{used}\ (a-b)^2=a^2-2ab+b^2\\\\(x-2)^2=-8+4\\\\(x-2)^2=-4\\\\Answer:\ No\ real\ solution\ x\in\O\ \wedge\ y\in\O [/tex]
