Chapter 9 - 9.1 - Linear and Nonlinear Systems of Equations - 9.1 Exercise - Page 636: 29

$(0,0),$ $(-2,4)$

From the first equation, $y=x^{2}$ (Isolation). Consider the second equation, $2x+y=0$ This becomes: $2x+x^{2}=0$ (Substitution). Thus, $x^{2}+2x=0$ $x(x+2)=0$ This gives $x=0,$ and $x=-2$ Accordingly, $y=0,$ and $y=4$