Chapter 3 - Section 3.1 - Systems of Linear Equations in Two Variables - 3.1 Exercises - Page 227: 57

$x=0$ $y=0$

If we multiply the first equation by $2$, then we add the two equations, we can eliminate the $y$ from the system: $2x+2y=0\times2$ $2x-2y=0$ $4x=0$ $x=0$ $0+y=0$ $y=0$ We have to check, if the solution is right. Substitute $x$ with 0 and $y$ with 0: $0+0=0$ $\checkmark$ $2(0)-2(0)=0$ $\checkmark$